Removed non present Octave files from setup.py
Apparently cf02744 was wrong.
Dropped rotate multi vectorization feature, simplified tests and code
This code was too "magical" and obscure and, although practical,
very difficult to understand. I prefer dropping this and other
features and keeping the code simpler.
Dropped poliastro.constants, using Astropy
Maybe pending better integration with Astropy Quantities.
Dropped several Julian Day utility functions, use astropy.time
Rolled back vectorization of twobody functions