added new contributors
fixed typo: cython3 instead of cython in python3-based installation instructions in ubuntu
Fixed broken docs
added dist measures to docs
minor edits
added more qobj methods
minor rewording of intro
cleaned up states guide
Updated docs

- added homebrew installation instrctions
- Updated steady state stuff.
- Updated td section for new complex c-math.
- updated organizational plot
Added 3.1.0 change log
revised platform independent pip installation section
minor editing homebrew section
minor editing macport section
fix typo
added new functions to apidoc list
New doc section for super_tensor, composite and tensor_contract.
Merge pull request #15 from jrjohansson/updates-docs-3.1.0

Updates docs 3.1.0
Added note on new tensor functions.
updated function/classes indices
updates to docs