Use a semaphore to prevent concurrency issues between Java Activity and Native thread code, when using 'Android_Window'.
(Eg. Java sending Touch events, while native code is destroying the main SDL_Window. )
Expand SDLActivity::SDLSurface::surfaceChanged() callback to grab the panel width and height at the same time and pass that along to the native code. Only works on API 17+. Duplicates surface dimensions whenever it fails.
Add Android_DeviceWidth/Android_DeviceHeight globals to native code.
Disambiguate Android_ScreenWidth/Android_ScreenHeight -> Android_SurfaceWidth/Android_SurfaceHeight
Use device width/height for all display mode settings.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
