Changes

Creating, and running, such a testsuite is a crucial part of improving the open web. Whenever a technology has multiple implementations it's very easy to introduce accidental discrepancies that cause poor interoperability. Historically this has been a problem on the web with different browsers all having their own quirks that developers have had to learn and work around. By contributing to the web-platform-tests testsuite we can build up a repository of test cases that can be run by all browser vendors through their development cycle so such issues are caught before they make it into released builds. The aim of this project is to allow us to run the full set of web-platform-tests in geckoGecko and Servo, and create an easy workflow for contributing tests back to the upstream.