Added a note that states the add-on requires Blender 2.78+. Even though
this isn't strictly true (it also supports 2.77a if you manually install
the Blender ID add-on), it simplifies things greatly.
Fixes T49721
Refactor of pillar-server and pillar-web into a single python package. This
simplifies the overall architecture of pillar applications.
Special thanks @sybren and @venomgfx