Add TeamCity code coverage

[Daniel15]

Added support for retrieving code coverage from Codebetter TeamCity.

[espadrine]

This is a pretty good pull request! Thanks again!

There is a small typo. If you wish to fix it, I'd be most grateful. The name of the new function you built is coveragePercentageColor, but you called it as coveragePercentageColour on line 627.

[Daniel15]

Sorry about that! I originally called it coveragePercentageColour but renamed it to coveragePercentageColor just before sending the pull request. I guess I missed one of the calls.

[Daniel15]

Ugh I edited the file via the Github interface and it looks like it totally messed it up and for some reason the whole file is marked as changed. THANKS GITHUB <_<
I'll get it fixed.

[Daniel15]

@espadrine - This should be fine to merge now - Did you have any other changes you'd like me to do? Thanks!

[espadrine]

I noticed that the path used is a bit backwards compared to the other URLs. Besides, it causes overlap in the way TeamCity CodeBetter badges were captured (the /teamcity/codebetter/….svg URL, which gives test passing states, can capture /teamcity/codebetter/…/coverage.svg URLs).

I chose to change it to something like this: /teamcity/coverage/bt1242.svg. Tell me if you disagree with this choice.