Multiview: support cltr+click rename for non left/right views
Multiview: fix for crash when stereo was off
Multiview - refactor image: first step to image editor refactor, not working yet

* showing 3d only when image is 3d and show 3d is on
* setting show_stereo as default mode for image editor

Conflicts:
	source/blender/blenloader/intern/readfile.c
	source/blender/editors/space_image/image_buttons.c
Multiview: refactor image - second step, not working yet

* image and Imageuser flags re-arranged
* image IMA_IS_STEREO flag set when opening image =)
* ALSO fix for stereo always on - or better, to TripleBuffer always on
Multiview: refactor image - third step, not working yet

2D is working, the missing bit is the stereo now
Multiview: refactor image - fourth step, missing details

All that is missing now is to refresh the buffers without having to change the layer