Add a FAQ for contribution/troubleshooting questions.
Review Request #7971 — Created Feb. 17, 2016 and submitted — Latest diff uploaded
This provides the beginning of a FAQ where we can gather answers to common questions for contributing or troubleshooting dev installs. Right now, it just has a question on pull requests and a solution for some unit test failures on MacOS X 10.11.
Built the docs and made sure they looked correct.