No bug - Fix broken tags. DONTBUILD
Bug 978333 - Try to use localhost for marionette webserver if possible. r=jgriffin
Bug 979299 - Reduce fragility in real time test. r=dburns

Sometimes the clock.sleep(0.1) may take shorter than 0.1 seconds.  This
isn't a test about precision in Python, but rather that the SystemClock
wrapper works as intended and returns a somewhat expected value.