New option "move texture channel up/down" lacked redraw calls.
Featurette:
There's still no manipulator handles for lamps to set cone size, dist,
clipping. To save our poor Peach artists hours of work I've added a
quick method to at least be able to do it interactive.
Option is hidden behind Wkey, and uses a similar function like Scaling.
(Put mouse cursor close to start value, move mouse to center of lamp)
Ultimately this should move to custom manipulator handles...