Use a coverage service

[artginzburg]

Pick the best one from here https://npm.im/fetch-coverage

[artginzburg]

So, I added the following coverage services to test them all out:

• Code Climate (a9e01df...860aaa4)
• Codecov (ce01adb...d4762bb)
• Scrutinizer (without the coverage uploading yet, I'm gonna test out the other features)
• Coveralls (9d13d61)