Refactored SDL_EGL_CreateContext: It now supports context flags and OpenGL ES 3+ contexts, and its behavior more closely matches the GLX and WGL context creation code.
Improved the code style consistency of SDL_egl.c.
Fixes bugzilla #2865.
2 * http://wiki.libsdl.org/moin.cgi/Roadmap
5 3554 - Need to resolve semantics for locking keys on different platforms
6 4874 - Do we want screen rotation? At what level?
7 4974 - Windows file code needs to convert UTF-8 to Unicode, but we don't need to tap dance for Windows 95/98
8 4865 - See if this is still needed (mouse coordinate clamping)
9 4866 - See if this is still needed (blocking window repositioning)