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/screenids.h

@@ -0,0 +1,50 @@
+#ifndef __SCREEN_IDS
+#define __SCREEN_IDS
+
+enum ScreenTypes
+{
+	EDIT_SCREEN,
+	SAVING_SCREEN,
+	LOADING_SCREEN,
+	ERROR_SCREEN,
+	INIT_SCREEN,
+	GAME_SCREEN,
+	ANIEDIT_SCREEN,
+	PALEDIT_SCREEN,
+	DEBUG_SCREEN,
+	MAP_SCREEN,
+	LAPTOP_SCREEN,
+	LOADSAVE_SCREEN,
+	MAPUTILITY_SCREEN,
+	FADE_SCREEN,
+	MSG_BOX_SCREEN,
+	MAINMENU_SCREEN,
+	AUTORESOLVE_SCREEN,
+	SAVE_LOAD_SCREEN,
+	OPTIONS_SCREEN,
+	SHOPKEEPER_SCREEN,
+	SEX_SCREEN,
+	GAME_INIT_OPTIONS_SCREEN,
+	DEMO_EXIT_SCREEN,
+	INTRO_SCREEN,
+	CREDIT_SCREEN,
+	MP_JOIN_SCREEN, // OJW - 20081129
+	MP_HOST_SCREEN,
+	MP_SCORE_SCREEN, // OJW - 20081222
+	MP_CHAT_SCREEN, // OJW - 20090315
+	MP_CONNECT_SCREEN, //OJW - 20090422
+	MINIGAME_SCREEN,		// Flugente
+	FEATURES_SCREEN, //rftr
+
+#ifdef JA2BETAVERSION
+	AIVIEWER_SCREEN,
+#endif
+
+//#ifdef JA2BETAVERSION
+	QUEST_DEBUG_SCREEN,
+//#endif
+
+	MAX_SCREENS
+};
+
+#endif