Color total warning count depending on number of warnings

If there are no warnings, the output will be green, other wise it will
be green.

Fixes #287
Ok. I thought it would be wasteful to set the color mode before all the tests if we could do it only once. 

I'm guessing your previous message should read: We shouldn't use.

I just googled before :all and saw there could be some issues. I'll change it.