[SUGGESTION] Add an "issue template"

[tetedange13]

Hi,

I tried to answer myself some issues about CNVkit and in my tiny experience, people tend to give too little details about what they were doing experiencing their bug ! => CNVkit is a quite simple tool to use, but with a lot of custom possiblilities (BTW thanks again for your investment developing it !!) => My point is: have you ever considered using a Github issue template ?

I did one myself here, based on what I thought accurate for bug repporting on CNVkit => Help yourself with it! (inspired from https://github.com/devspace/awesome-github-templates)

Hope this helps. Have a nice day. Felix