improve gl_rendererer_attach failure handling
gl_renderer_attach doesn't handle failure very well - if it fails to create an EglImage in a multi-plane format, it will continue and leave us with a sparsely correct array to deal with later.
It would probably be better to:
- stop creating new images when one fails
- dispose of any previously created images immediately
- use some kind of placeholder for display
Edited by Derek Foreman