Tim McDaniel
Using checkkeys test app:
* Press and hold Caps Lock key.
* checkkeys reports a CapsLock key pressed event and a CapsLock key released event.
* Release Caps Lock key.
* checkkeys reports no further events.
This patch fixes OSX Caps Lock up/down event detection by installing a HID callback.
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().
