As discussed during the developer hangout of 2015-03-31, this commit
removes support for VTKv5.

Most of the h/cxx files have been updated automatically using the
script "slicer_remove_vtk5_support.py" [1]. See below.

The remaining of h/cxx, python and CMake files have been updated
manually.


slicer_remove_vtk5_support.py:
cd ~/Project/Slicer
~/Download/slicer_remove_vtk5_support.py $(ack -l VTK_MAJOR_VERSION)

[1] https://gist.github.com/jcfr/91d2f5d07c2a36320e48

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24801 3bd1e089-480b-0410-8dfb-8563597acbee