Enabled precompiled headers for the build. This cuts the win compile time in debug by at least half on my laptop; on the psp compile, it shaves it down by ~ 45 seconds. I only did a cursory inspection of what to add to PrecompiledHeader.h, there's probably more that we can throw in there for more incremental speed improvements.

Also fixed the project includes so that we don't need to always use the indirect include path, ie:
#include "../include/foo.h" -> #include "foo.h"

I'm don't know much about make files - if I busted the linux build, mea culpa, but I think we're okay on that front too.  For future reference, here's the most straightforward link on the topic of adding pch support to make files:

http://www.mercs-eng.com/~hulud/index.php?2008/06/13/6-writing-a-good-makefile-for-a-c-project

projects/mtg/include/GameStateOptions.h

@@ -3,7 +3,7 @@
 
 #include <JGE.h>
 #include <JGui.h>
-#include "../include/GameState.h"
+#include "GameState.h"
 
 class GameApp;
 class WGuiTabMenu;