Increment version number to v2.56

That makes it official! :D

Author: IQAndreas

src/org/flixel/FlxG.as

@@ -37,7 +37,7 @@ package org.flixel
 		 * Assign a minor version to your library.
 		 * Appears after the decimal in the console.
 		 */
-		static public var LIBRARY_MINOR_VERSION:uint = 55;
+		static public var LIBRARY_MINOR_VERSION:uint = 56;
 
 		/**
 		 * Debugger overlay layout preset: Wide but low windows at the bottom of the screen.