Merge pull request #61 from bchretien/master

Add initial matplotlib support.
matplotlib: install missing header.
matplotlib.hh: support "from ... import ..." for matplotlib.
matplotlib-function.hh: treat outputSize == 1 case separately.
Update README.md

Add Zenodo DOI.
Update README.md
Update README.md
Update README.md
[travis] Enable build on Mac OS X
[travis] Allow failure on OSX.

This can be removed once OSX-related settings are added.