<bugfix>In VTK package: Added support for Qt4.6 to TransferFunctionWidget</bugfix> <feature>In VTK package: TransferFunction is now serialized as XML because pickle serialization  works with python only. Old workflows are still supported.</feature>
<bugfix>In VTK package: Added support for Qt4.6 to TransferFunctionWidget</bugfix>
<feature>In VTK package: TransferFunction is now serialized as XML because pickle serialization 
works with python only. Old workflows are still supported.</feature>

vistrails/packages/vtk/tf_widget.py
 - Added unit tests for new methods
 - Replaced conversion functions in TransferFunctionConstant

 class TransferFunction:
  new methods:
   serialize
   parse

 class TransferFunctionPoint:
  __init__():
    setting flag ItemSendsGeometryChanges for Qt4.6 support

 class TransferFunctionWidget:
  __init__():
    replaced pickle call with TransferFunction.parse()
  contents():
    replaced pickle call with TransferFunction.serialize()
  setContents():
    replace pickle call with TransferFunction.parse()

celiafish/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,minesense/VisTrails,minesense/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,minesense/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,Nikea/VisTrails,celiafish/VisTrails,minesense/VisTrails,Nikea/VisTrails,hjanime/VisTrails,minesense/VisTrails,hjanime/VisTrails