Bug 1076810 - RelEng CI tests should be available over the internet, not just from VPN:

This patch:
1) Colourises the test output, making it easier to see at a glance which tests passed/failed
2) Publishes the coverage reports to coveralls (and does not cause build to fail if publish fails)
3) Adds a README.md to tools, for getting an overview when viewing in github

r=rail