New vehicle RV take two Ready to go! [CR]

Saw this pull request #2053 and nobody seemed to be working on it anymore.  Didn't get any responses on the comments, so I thought I would try to finish this myself, as I always thought it was strange Cata didn't have an RV.  So far, I think I have the design in veh_typedef.cpp fixed (It had a LOT of bugs, like vp_board on every tile, so it was basically a solid block of metal on wheels) but I'm not quite sure how to add this to Magen.cpp so it will spawn in game.  Can anyone give me some advice on this?

EDIT - This should be ready for review, I've tested it and it works.  It does add a new vehicle part (underbody wide wheels) though so if that's a problem tell me and I'll rework it some more.