Improve jrunscript io definitions

Also:
* fix broken documentation link for jsh loader

jrunscript/jsh/_.fifty.ts

@@ -109,7 +109,7 @@ namespace slime.jsh {
  * of a script.  It has two implementations: a Rhino implementation (`inonit.script.jsh.Rhino`) and a Nashorn implementation
  * (`inonit.script.jsh.Nashorn`); the entry point is chosen and executed by the launcher subsystem.
  *
- * It is documented at {@link slime.jsh.loader.internal}.
+ * It is documented at {@link slime.jsh.internal.loader}.
  *
  * ## Development Tools
  *

loader/jrunscript/io.fifty.ts

@@ -7,12 +7,19 @@
 namespace slime.jrunscript.runtime.io {
 	type byte = number
 
+	export namespace input {
+		export interface ReaderConfiguration {
+			charset: string
+			LINE_SEPARATOR: string
+		}
+	}
+
 	/**
 	 * A stream from which bytes may be read.
 	 */
 	export interface InputStream {
 		/** A character input stream that reads this stream. */
-		character: (mode?: any) => Reader
+		character: (mode?: input.ReaderConfiguration) => Reader
 
 		/**
 		 * Closes the underlying stream.

loader/jrunscript/io.js

@@ -21,9 +21,17 @@
 		var _java = $context._streams;
 
 		function InputStream(peer) {
+			/**
+			 *
+			 * @param { slime.jrunscript.runtime.io.input.ReaderConfiguration } [mode]
+			 * @returns
+			 */
 			var character = function(mode) {
-				if (!mode) mode = {};
-				if (!mode.charset) mode.charset = Packages.java.nio.charset.Charset.defaultCharset().name();
+				if (!mode) mode = {
+					charset: void(0),
+					LINE_SEPARATOR: void(0)
+				};
+				if (!mode.charset) mode.charset = String(Packages.java.nio.charset.Charset.defaultCharset().name());
 				var separator = mode.LINE_SEPARATOR;
 				//	TODO	No unit test for this method currently; does it work?
 				return Reader(new Packages.java.io.InputStreamReader(peer,mode.charset), {LINE_SEPARATOR: separator});