Update with edition idioms.

examples/add.rs

@@ -15,13 +15,9 @@
 #![deny(warnings)]
 #![allow(trivial_casts)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::Repository;
+use serde_derive::Deserialize;
 use std::path::Path;
 
 #[derive(Deserialize)]
@@ -71,7 +67,7 @@ fn run(args: &Args) -> Result<(), git2::Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: add [options] [--] [<spec>..]
 
 Options:

examples/blame.rs

@@ -12,13 +12,9 @@
  * <http://creativecommons.org/publicdomain/zero/1.0/>.
  */
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{BlameOptions, Repository};
+use serde_derive::Deserialize;
 use std::io::{BufRead, BufReader};
 use std::path::Path;
 
@@ -91,7 +87,7 @@ fn run(args: &Args) -> Result<(), git2::Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: blame [options] [<spec>] <path>
 
 Options:

examples/cat-file.rs

@@ -14,15 +14,11 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use std::io::{self, Write};
 
 use docopt::Docopt;
 use git2::{Blob, Commit, ObjectType, Repository, Signature, Tag, Tree};
+use serde_derive::Deserialize;
 
 #[derive(Deserialize)]
 struct Args {
@@ -132,7 +128,7 @@ fn show_sig(header: &str, sig: Option<Signature>) {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: cat-file (-t | -s | -e | -p) [options] <object>
 
 Options:

examples/clone.rs

@@ -14,14 +14,10 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::build::{CheckoutBuilder, RepoBuilder};
 use git2::{FetchOptions, Progress, RemoteCallbacks};
+use serde_derive::Deserialize;
 use std::cell::RefCell;
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
@@ -52,7 +48,7 @@ fn print(state: &mut State) {
     let kbytes = stats.received_bytes() / 1024;
     if stats.received_objects() == stats.total_objects() {
         if !state.newline {
-            println!("");
+            println!();
             state.newline = true;
         }
         print!(
@@ -115,13 +111,13 @@ fn run(args: &Args) -> Result<(), git2::Error> {
         .fetch_options(fo)
         .with_checkout(co)
         .clone(&args.arg_url, Path::new(&args.arg_path))?;
-    println!("");
+    println!();
 
     Ok(())
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: add [options] <url> <path>
 
 Options:

examples/diff.rs

@@ -14,16 +14,11 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
-use std::str;
-
 use docopt::Docopt;
 use git2::{Diff, DiffOptions, Error, Object, ObjectType, Repository};
 use git2::{DiffFindOptions, DiffFormat};
+use serde_derive::Deserialize;
+use std::str;
 
 #[derive(Deserialize)]
 #[allow(non_snake_case)]
@@ -64,11 +59,11 @@ struct Args {
     flag_git_dir: Option<String>,
 }
 
-const RESET: &'static str = "\u{1b}[m";
-const BOLD: &'static str = "\u{1b}[1m";
-const RED: &'static str = "\u{1b}[31m";
-const GREEN: &'static str = "\u{1b}[32m";
-const CYAN: &'static str = "\u{1b}[36m";
+const RESET: &str = "\u{1b}[m";
+const BOLD: &str = "\u{1b}[1m";
+const RED: &str = "\u{1b}[31m";
+const GREEN: &str = "\u{1b}[32m";
+const CYAN: &str = "\u{1b}[36m";
 
 #[derive(PartialEq, Eq, Copy, Clone)]
 enum Cache {
@@ -267,7 +262,7 @@ impl Args {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: diff [options] [<from-oid> [<to-oid>]]
 
 Options:

examples/fetch.rs

@@ -14,13 +14,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{AutotagOption, FetchOptions, RemoteCallbacks, Repository};
+use serde_derive::Deserialize;
 use std::io::{self, Write};
 use std::str;
 
@@ -123,7 +119,7 @@ fn run(args: &Args) -> Result<(), git2::Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: fetch [options] [<remote>]
 
 Options:

examples/init.rs

@@ -14,13 +14,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{Error, Repository, RepositoryInitMode, RepositoryInitOptions};
+use serde_derive::Deserialize;
 use std::path::{Path, PathBuf};
 
 #[derive(Deserialize)]
@@ -129,7 +125,7 @@ fn parse_shared(shared: &str) -> Result<RepositoryInitMode, Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: init [options] <directory>
 
 Options:

examples/log.rs

@@ -14,15 +14,10 @@
 
 #![deny(warnings)]
 
-#[macro_use]
-extern crate serde_derive;
-extern crate docopt;
-extern crate git2;
-extern crate time;
-
 use docopt::Docopt;
 use git2::{Commit, DiffOptions, ObjectType, Repository, Signature, Time};
 use git2::{DiffFormat, Error, Pathspec};
+use serde_derive::Deserialize;
 use std::str;
 
 #[derive(Deserialize)]
@@ -274,7 +269,7 @@ impl Args {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: log [options] [<commit>..] [--] [<spec>..]
 
 Options:

examples/ls-remote.rs

@@ -14,13 +14,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{Direction, Repository};
+use serde_derive::Deserialize;
 
 #[derive(Deserialize)]
 struct Args {
@@ -47,7 +43,7 @@ fn run(args: &Args) -> Result<(), git2::Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: ls-remote [option] <remote>
 
 Options:

examples/rev-list.rs

@@ -15,13 +15,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{Error, Oid, Repository, Revwalk};
+use serde_derive::Deserialize;
 
 #[derive(Deserialize)]
 struct Args {
@@ -93,7 +89,7 @@ fn push(revwalk: &mut Revwalk, id: Oid, hide: bool) -> Result<(), Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: rev-list [options] [--] <spec>...
 
 Options:

examples/rev-parse.rs

@@ -14,13 +14,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::Repository;
+use serde_derive::Deserialize;
 
 #[derive(Deserialize)]
 struct Args {
@@ -54,7 +50,7 @@ fn run(args: &Args) -> Result<(), git2::Error> {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: rev-parse [options] <spec>
 
 Options:

examples/status.rs

@@ -14,13 +14,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{Error, ErrorCode, Repository, StatusOptions, SubmoduleIgnore};
+use serde_derive::Deserialize;
 use std::str;
 use std::time::Duration;
 
@@ -415,7 +411,7 @@ impl Args {
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage: status [options] [--] [<spec>..]
 
 Options:

examples/tag.rs

@@ -14,13 +14,9 @@
 
 #![deny(warnings)]
 
-extern crate docopt;
-extern crate git2;
-#[macro_use]
-extern crate serde_derive;
-
 use docopt::Docopt;
 use git2::{Commit, Error, Repository, Tag};
+use serde_derive::Deserialize;
 use std::str;
 
 #[derive(Deserialize)]
@@ -80,7 +76,7 @@ fn print_tag(tag: &Tag, args: &Args) {
     if args.flag_n.is_some() {
         print_list_lines(tag.message(), args);
     } else {
-        println!("");
+        println!();
     }
 }
 
@@ -89,7 +85,7 @@ fn print_commit(commit: &Commit, name: &str, args: &Args) {
     if args.flag_n.is_some() {
         print_list_lines(commit.message(), args);
     } else {
-        println!("");
+        println!();
     }
 }
 
@@ -106,15 +102,15 @@ fn print_list_lines(message: Option<&str>, args: &Args) {
     if let Some(first) = lines.next() {
         print!("{}", first);
     }
-    println!("");
+    println!();
 
     for line in lines.take(args.flag_n.unwrap_or(0) as usize) {
         print!("    {}", line);
     }
 }
 
 fn main() {
-    const USAGE: &'static str = "
+    const USAGE: &str = "
 usage:
     tag [-a] [-f] [-m <msg>] <tagname> [<object>]
     tag -d <tag>