Blender Git Loki

Correct texture pinning:
* Now texture pinning works consistently for all textures.
* The only problem is that there is no way to pin textures if there are
no textures in the context path, so it's for example impossible to pin
the texture of a displace modifier without adding a texture somewhere
else and selecting that texture first. I my opinion this is quite
counter productive so perhaps a dedicated "only textures" texture
context option is needed after all.