Use our own fork of Slicer for VesselView
Update Applications folder after Slicer update
Bump TubeTK for vtk6 support
Welcome screen: Make everything compile/load

Initial simple/commit. Nothing works correclty so far, it's just a first
step to allow everything to load correctly.
Welcome screen: Welcome module

The welcome module is essentially here to select the correct layout. It
also takes care of hiding most of the undisired interface.
Welcome screen: first pass at the qml

Create the list of modules on the left side panel
Welcome screen: second pass at the qml

Finished it and it is now ready to link with the c++ to open the desired
module.
Welcome screen: open module once the open in vesselview is clicked
Welcome screen: add return to welcome button
Welcome screen: Developer mode hack

-d or --developer will start vesselview without the welcome module, thereby
getting rid of the welcome layout and user offuscation.
It's hackish however since it gets rid of some settings and artificially
remove the Welcome module from the loaded modules.
It's also not listed in the help module.
Welcome screen: replace PNG logos by SVG
Merge branch 'WelcomeInterface'

* WelcomeInterface:
  Welcome screen: replace PNG logos by SVG
  Welcome screen: Developer mode hack
  Welcome screen: add return to welcome button
  Welcome screen: open module once the open in vesselview is clicked
  Welcome screen: second pass at the qml
  Welcome screen: first pass at the qml
  Welcome screen: Welcome module
  Welcome screen: Make everything compile/load
  Bump TubeTK for vtk6 support
  Update Applications folder after Slicer update
  Use our own fork of Slicer for VesselView