more integration test debug tools

Going back to buildbot_travis, I realize this was still not too easy to debug in case of failure. Sorry about noise.

printBuild: Print the colored logs if the step has failed
tearDown: Print all builds if the test is failing

I think most of the unit test debugging is done via command line trial.
All the log.msg are in the _trial_temp/test.log, which are not by default in the console terminal

 I use this shell function to run trial for development, which acts a little bit like "gulp dev"
It reruns your unit tests forever as soon as you save your files.

    ttrial () {
            args=$*
            trial $args
            watchmedo shell-command --patterns="*.py" --recursive --command "trial $args"
    }

Then the colors are here to simulate coloring output in the UI. it helps localizing the errors from the headers.