gitadora: (arena model) single window mode + subscreen overlay (#486)

## Link to GitHub Issue, if one exists
#477 

## Description of change
This is a work in progress.

What works:
- [x] subscreen overlay shows the touch screen image (in windowed mode)
- [x] touch works in the overlay
- [x] only the main window is shown, other windows are not launched

What doesn't:
- [ ] game occasionally crashes when entering test menu?
- [ ] full screen mode is not tested at all due to monitor requirements
- [ ] need more polish (various options to control the behavior)

src/spice2x/misc/wintouchemu.cpp

@@ -10,6 +10,7 @@
 #include <thread>
 
 #include "cfg/screen_resize.h"
+#include "games/gitadora/gitadora.h"
 #include "games/iidx/iidx.h"
 #include "hooks/graphics/graphics.h"
 #include "overlay/overlay.h"
@@ -390,7 +391,10 @@ namespace wintouchemu {
                 } else if (avs::game::is_model("LDJ") && !GENERIC_SUB_WINDOW_FULLSIZE) {
                     // overlay subscreen in IIDX
                     // use mouse position as ImGui overlay will block the touch window  
-                    log_info("wintouchemu", "use mouse cursor API for overlay subscreen");
+                    log_info("wintouchemu", "use mouse cursor API for ldj overlay subscreen");
+                    USE_MOUSE = true;
+                } else if (games::gitadora::is_arena_model() && games::gitadora::ARENA_SINGLE_WINDOW) {
+                    log_info("wintouchemu", "use mouse cursor API for gitadora overlay subscreen");
                     USE_MOUSE = true;
                 } else {
                     // create touch window - create overlay if not yet existing at this point