code cleanup


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55377 954f8c5b-7b00-dc11-b283-0030488c597c
Node Editor / Group UI:
* Add, Move and Remove Socket operators missed a notifier for UI redraw.

Note: ND_DISPLAY seems to be for the Text editor only, according to WM_types.h, but seems to be used in quite a few places. 
Time to cleanup notifiers again. 


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55378 954f8c5b-7b00-dc11-b283-0030488c597c
UI fix: drawing disabled buttons now draw OK in all cases.

The old 2.5 code was just drawing a blended rect over buttons, which looks bad
in cases the backdrop is undefined. 

Now widget drawing code just draws everything half transparent. Much nicer!
Time for textured backdrops? ;)



git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55379 954f8c5b-7b00-dc11-b283-0030488c597c