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/Intro.h

@@ -0,0 +1,45 @@
+#ifndef _INTRO__C_
+#define _INTRO__C_
+
+
+
+UINT32	IntroScreenShutdown( void );
+UINT32	IntroScreenHandle( void );
+UINT32	IntroScreenInit( void );
+
+void	StopIntroVideo();
+
+//enums used for when the intro screen can come up, used with 'gbIntroScreenMode'
+enum EIntroType
+{
+#ifdef JA2UB	
+	INTRO_HELI_CRASH,
+#endif
+	INTRO_BEGINNING,			//set when viewing the intro at the begining of the game
+	INTRO_ENDING,				//set when viewing the end game video.
+
+	INTRO_SPLASH,
+};
+
+
+extern	UINT32	guiSmackerSurface;
+
+
+void SetIntroType( INT8 bIntroType );
+extern void		DisplaySirtechSplashScreen();
+extern UINT32		guiIntroExitScreen;
+extern BOOLEAN		gfIntroScreenExit;
+extern INT8 gbIntroScreenMode;
+
+#define MAX_VIDEO_NAMES_CHARS		128
+
+typedef struct
+{
+	UINT16		uiIndex; 
+	CHAR16	szFile[MAX_VIDEO_NAMES_CHARS];
+
+} INTRO_NAMES_VALUES;
+
+extern INTRO_NAMES_VALUES zVideoFile[255];
+
+#endif