Tor Browser Bundle build for Android

Mike thinks we're not that far from being able to try a Tor Browser Bundle build on Android.

The main blocker he sees currently is Torbutton, since "FF mobile's crazy multi process model breaks various listeners in strange ways" and "Torbutton listens to a ton of request observers that are complicated by a multi-process model". See #5279 (closed) and #3100 (closed) for subtasks Mike expects will be needed along the way to making Torbutton work for FF mobile.

But in the mean time, we could make a Tor Browser Bundle with Proxy Mobile as the proxy forcer addon. (Nathan, how much does that plan differ from how Orweb works today?)

Then it would be an incremental set of steps for Mike to add Torbutton-like features into Proxy Mobile. Specifically, Mike says "I think the way to go is to copy+paste torbutton features into that thing, starting with easiest-first. And if that goes well, we'll start using it on the desktop, too (since we want to gut so much shit out of desktop torbutton anyway)"