fix for G,G causing vertex slide in UV/Image window, also comment unused defines/enums.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54068 954f8c5b-7b00-dc11-b283-0030488c597c
Fix #33975: Crash when reloading texture

Two issues in texture_changed:
- Missing NULL check for material (slot could be empty)
- Materials could be linked to object, added special check for this

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54069 954f8c5b-7b00-dc11-b283-0030488c597c