Added some features on my fork: option to pass zip file, extra languages, pip package organization

[SynapticSage]

Would you be interested in pulling these?

https://github.com/SynapticSage/github2file/tree/zipfile_and_multilang_option

• restructured it into a pip package
• added extra languages to the standard script
• ability to filter multiple languages in a single pass (one text file): --lang "python,html,css" extracts python, html, and css in one pass.
• added option to pass in zip file directly

the latter is useful for when you have a private repo. I believe another issue in this repo proposed a mechanism via github keys. but to me this opens it up to other services like private gitlab or bitbucket repos.

Also given it's a module in this version, it's called via

python -m github2file [arguments]