docs(troubleshooting) - Add a troubleshooting section

I've spent a lot of time reading Karma issues. I think it would be nice if there was a troubleshooting section with steps that people could follow to try to debug common issues. What do you guys think?

CLA signed: Rob Dodson
Merge pull request #844 from robdodson/patch-1

docs(troubleshooting) - Add a troubleshooting section