Matlab compatibility and HTML docs

Better API compatibility with Matlab Mapping Toolbox.

HTML docs for Matlab and Python.

Matlab and cleanup

• Added several Matlab/Octave functions (save $1000 on Matlab Mapping Toolbox).
• cleaned up self-test

Python 2.7 - 3.7 compatible

On request Python 2.7 - 3.7 compatible.

Also added fallback simpler (but less accurate) functions where AstroPy not available.

prereqs

PEP8, standardize setup.py

py27-py36

v1.2.3

bump [ci skip]

Vincenty, API

v.1.2.2

py35

Python 3D coordinate conversions for geospace

v1.0

doc