made event handlers in interpreter public
replaced drawing signalling pathway by controler calls
merge
Merge branch 'interactionmodes'

Conflicts:
	volumina/brushingcontroler.py
	volumina/volumeEditor.py
deactivated brushinginterpreter; activate again, when navIntrp is no longer responsible for drawing
removed legacy code: penVis and penDraw
using brushing model directly in navInterpr
removed unnecessary brush setting signalling redirections
fixed (dis|en)able erasing. Was broken after last refactoring.
activeView does not need to be a property
Fixed color related drawing bug.
Merge branch 'master' of github.com:Ilastik/volumina
refactor tiling datastructures, tile progress indicator,fix property bug

* fix 'property' object not callable:
  the problem was that QGraphicsItem implements it's own shape()
  function which we overwrote in CrosshairCursor and
  SliceIntersectionMarker with our own shape _property_ getter/setter.
  Obviously this is not allowed

* Implement the 'pie' progress indicators for each tile with a
  QGraphicItem derived class instead of drawing on top of patches.
  Also fixes the correct progress info on slice change.

* Rewrite tiling datastructures which hold the tiled images for each
  layer. This is broken down into multiple classes.
enabled brushing interpr again
removed drawing code from navInterpr
Interpreter abstract base class
implemented start and finalize hooks for interaction interpreters
replaced setDrawingEnabled with setInteractionMode
make slice intersection marker colors consistent
Merge branch 'master' of https://github.com/Ilastik/volumina