Bug 886165 - Hide the alternate names in the spec behind prefs which are turned off by default; r=roc

This patch uses one pref per interface, to allow us finer grain control over
which ones we might need to turn on in the future.
Bug 885583 - Enable Web Audio unconditionally across mochitests; r=roc
Merge mozilla-central into mozilla-inbound
Remove two unused variables in nsNSSCertificateDB.cpp, no bug
Bug 882890 - Add fake vertex attribute 0 disabling to the getVertexAttrib function to improve WebGL compatibility with driver limitations. r=bjacob