This change-set fixes a lot of windowing related bugs, especially with
regards to Windows 8.x apps running on Windows 10 (which was the driver for
this work). The primary fixes include:
* listed display modes were wrong, especially when launching apps into a
non-fullscreen space
* reported window flags were often wrong, especially on Windows 10
* fullscreen/windowed mode switches weren't failing (they are not
programmatically possible in Win 8.x apps).
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().
