Copter: Add support for V-Tail Quads

Something to note is that the pitch is backwards (not sure how to change my values at the moment to fix that) - so I just reversed pitch on my remote, and it works fine.

For motor rotation and position, it's the exact same as the Quad X.

Here is a video of the code in flight: https://www.youtube.com/watch?v=TDKzIVi3zYA