Consider adding a CONTRIBUTING file

[ldionne]

A CONTRIBUTING.md file at the root of the project can be useful to tell basic stuff to potential contributors, such as the branch to which pull requests should be directed. While it is currently unclear, I think we must submit PRs to master because develop is far behind. Is this correct?

[pfultz2]

Technically, they should go to develop, but right now i haven't been using the develop branch since there is not too much activity to warrant a separate branch. However, I will need to start using the develop branch when it moves into boost, I believe.

[ldionne]

Yes, I'm fairly sure you would have to.