Incorporated changes from https://github.com/openxc/openxc-python/blob/master/CONTRIBUTING.rst
Renamed 'contributing_details' to 'how_to_contribute'
Created contributing_tips_and_tricks file
Changed navigation link for 'Contributing Details' to 'How to Contribute'
Moved 'Tips and Tricks' from 'How To Contribute' to 'Contributing Tips and Tricks'
Added 'Contributing Tips' to the contributing nav bar