BUG: Fix missing icons in extension manager

Update qSlicerBaseQTGUI.qrc[1] to include icons for new tool menu in
extension manager. This fixes the button for the same having no icon on
systems that lack the themed icon, as the non-themed icon was being
specified and exists in the source tree, but was missing from the
aforementioned .qrc.

(1: http://www.slicer.org/slicerWiki/index.php/Documentation/Nightly/Developers/Build_system/Qt_resource_files)

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23479 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Ensure MultiVolume modules work with VTK 5 and 6

This commit updates the modules to check for the version
of VTK (using `vtk.VTK_MAJOR_VERSION`). This is required
because the MacOSX factory is still building against VTK5.

For more details see:

  fedorov/MultiVolumeExplorer@1053c40
  fedorov/MultiVolumeImporter@351226a

From: Andrey Fedorov <fedorov@bwh.harvard.edu>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23480 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Update SlicerWizard ExtensionDescription to detect file encoding

This commits updates the ExtensionDescriptionto support encoding
detection when either a filepath or a repo parameter is passed.