ellipsoid for other planets, more robust vincenty API and testing

Ellipsoid() now covers more Earth ellipsoid systems as well as a couple other planetary bodies such as Mars, Venus and the Moon. Feel free to pull request your own as usual, or ask.

Using Numpy ≥ 1.10.0 broadcast_to instead of tile in vreckon vdist to reduce memory usage and improve speed by using views instead of copies.