Web-platform-tests running in Servo

Servo, the Mozilla Research project to create a new browser engine using
the Rust programming language, is now using wptrunner to run a subset of
[1] the web-platform-tests in CI. The chosen tests roughly corresponding
to the current set of features and are expanding as more parts of the
platform are implemented. The results of these tests can be seen in the
Travis runs [2].

If anyone is interested, it should be quite possible to get the data
from these runs into a JSON-or-similar format that could be used to
compare with other browsers.

Thanks to Manish Goregaokar and Ms2ger who did most of the work to get
this running.

[1] https://github.com/servo/servo/blob/master/src/test/wpt/include.ini
[2] https://travis-ci.org/servo/servo (look for the AFTER_BUILD=wpt jobs)