add possibility to generate FBO with texture

The caller is responsible to delete the buffers. Depending on bRenderbuffer either with glDeleteRenderbuffers or with glDeleteTextures.

Change-Id: I5ccbd49862c381abf04e812765cced485a083f89
fix variable name

Change-Id: I1cfd6d59e5569177d8ad23245435073d30fe1374
reimplement custom sprite rendering with FBO

Change-Id: I8d7a54fac61a3072d4f34615e71e37c70dec4e50