Moved previous versions (C++, legacy XNA) to a 'legacy versions' directory.  Added the new Monogame-based version (which is pretty much the same as the XNA version with some basic changes to the solution and code, along with pre-compiled assets).  This is the version that multiplayer support will be added to.
Merge branch 'master' of https://github.com/Damaniel/TrackInsanity