Move main executable source to its own directory (#248)

* Move main executable files to their own directory

* Adapt the build to the new file structure

... and fix some weird #include's that were relying on the project root
being an include directory.

Ja2/MPScoreScreen.h

@@ -0,0 +1,12 @@
+#ifndef _MP_SCORE_SCREEN_H_
+#define _MP_SCORE_SCREEN_H_
+
+
+UINT32	MPScoreScreenInit( void );
+UINT32	MPScoreScreenHandle( void );
+UINT32	MPScoreScreenShutdown( void );
+
+
+
+
+#endif