use maxitest

Minitest + a bunch of useful features [maxitest](https://github.com/grosser/maxitest)

 - Ctrl+c stops tests and prints failures
 - print copy pastable rerun instructions on failure
 - multiple before & after blocks
 - around blocks around { |t| Dir.chdir(...) { t.call } }
 - red-green test output
 - mtest executable to run test by line number and by folder
 - let!
 - pending { assert false } is skip when it fails, but fails when it passes

![screen shot 2014-10-25 at 8 33 22 am](https://cloud.githubusercontent.com/assets/11367/4780183/61c08122-5c5c-11e4-92c0-1778d3bde9ad.png)

@pswadi-zendesk @adammw @sandlerr @dragonfax @princemaple @steved555 

### Risks
 - None