1. Quartz shadows are back: instead of casting shadows from selection view to pad view

(which means check 10^6 pixels every time if shadow path is not specified) set shadows in
a context - so Quartz knows exactly, what produces a shadow.
2. Remove "paint shadow" functions from pad painter.
3. Cleanup.


git-svn-id: http://root.cern.ch/svn/root/trunk@43491 27541ba8-7e3a-0410-8455-c3a389f83636