Add the various tokens/strings for the differnet texture types (2D, rect, oes)
Changes the GLmemory api to include the GstGLTextureTarget in all relevant
functions.
Update the relevant caps/templates for 2D only textures.
Add API for a helper object that can convert between different
stereoscopic video representations, and later do filtering
of multiple view streams.
https://bugzilla.gnome.org/show_bug.cgi?id=611157