refactored the code so that:
- EGL APIs that can be called before or after eglInitialize() will work by loading the drivers first
- make eglGetDisplay() a lot more efficient
- make sure that EGL drivers are loaded in a thread-safe way
- don't unload the drivers upon calling eglTerminate(), they're now never unloaded, since there is no safe way to do it (some thread could be running)
- updated our EGL version to 1.4
- return better error codes if errors happen during initialization
we now look for a config file in /system/lib/egl/egl.cfg that describes the association of a display to a driver.
these drivers are named: /system/lib/egl/lib{[EGL|GLESv1_CM|GLESv2] | GLES}_$TAG.so
