add field: programming languages used for implementation

[david-a-wheeler]

Add a field to record programming language is used for implementation, as a comma separated list. Many tools only support some specific languages, so we could provide better advice if we have this information. Others could more easily see how other projects that use the same language handle the criteria. Also, if we show this on the projexct list, some people would be incentivized to make sure their languages were well-represented.

[david-a-wheeler]

Note: "No languages" should be entered as "-", e.g., for documentation-only or test-suite-only projects. We can tell them to do that. That way, we can differentiate between "No answer" and "there are none".

This would be easy to automate, but perhaps we can start by not automating.

[david-a-wheeler]

GitHub provides an API to get this data; we could remove anything below a certain number of bytes (say 100) and short from large-to-small. See:
https://developer.github.com/v3/repos/#list-languages

[david-a-wheeler]

Commit 08c67f4 implements the manual part (without automation). I added this immediately, because then we can immediately start getting data from projects even without implementing automation.

[jdossett]

I agree using the GitHub API for GitHub repositories, but instead of using bytes, I suggest we use a percentage of total bytes given.

[david-a-wheeler]

We completed the manual field. See #943 for automation.