Bug 837139 - Performance test framework built on top of the integration tests

- Infrastructure for performance tests
- New Mocha reporter for perf tests
- Startup tests for sms, dialer, contacts and gallery
  (will be improved by bug 838527)
- Custom rendering time tests for the contacts app
  (will be continued in bug 837673)

Also, it makes the integration tests work again :)

Work done by @etiennesegonzac, @julienw and @Rik