Remove unnecessary includes of order.h. Add a placeholder main.cpp to…

… keep MPC/Visual Studio happy.

src/book/callback.h

@@ -3,7 +3,6 @@
 // See the file license.txt for licensing information.
 #pragma once
 
-#include "order.h"
 #include "types.h"
 
 namespace liquibook { namespace book {

src/book/liquibook.mpc

@@ -0,0 +1,10 @@
+project (liquibook): liquibook_exe {
+  exename = *
+  Header_files {
+    *.h
+  }
+  Source_Files {
+    *.cpp
+  }
+}
+

src/book/main.cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include "version.h"
+
+#include "depth_order_book.h"
+#include "order.h"
+
+using namespace liquibook;
+using namespace book;
+namespace
+{
+  // depth order book pulls in all the other header files.
+  // except order.h which is actually a concept.
+  DepthOrderBook<Order *, 5> unusedDepthOrderBook_;
+}
+
+int main(int, const char**)
+{
+    std::cout << "Liquibook version " << Version::MAJOR << '.' << Version::MINOR << '.' << Version::PATCH 
+      << " (" << Version::RELEASE_DATE << ")\n";
+    std::cout << "Liquibook is a header-only library.\n\n";
+    std::cout << "This executable is a placeholder to make the book header files visible in\n";
+    std::cout << "Visual Studio.  It also forces the compiler to do syntax checking of the header\n";
+    std::cout << "files at build time." << std::endl;
+    return 0;
+}
+

src/book/order_book.h

@@ -2,6 +2,7 @@
 // All rights reserved.
 // See the file license.txt for licensing information.
 #pragma once
+
 #include "version.h"
 #include "order_tracker.h"
 #include "callback.h"

src/book/order_listener.h

@@ -3,8 +3,6 @@
 // See the file license.txt for licensing information.
 #pragma once
 
-#include "order.h"
-
 namespace liquibook { namespace book {
 
 /// @brief generic listener of order events.  Implement to build a full order book feed.

src/book/order_tracker.h

@@ -4,7 +4,6 @@
 #pragma once
 
 #include "types.h"
-#include "order.h"
 
 namespace liquibook { namespace book {