* Added GLES, GLES2 and EGL packages to the ppremake files.
* New glesgsg and gles2gsg modules.
* Added egldisplay module that is like glxdisplay, but through the EGL library.
* Added pandagles and pandagles2 metalibs (only supporting egldisplay yet)
* The iphonedisplay module depends on glesgsg instead of embedding it.
* The glesext_shadow.h file is removed, we don't need it anymore.