Bug 1058297 - Allow opting-out of "build complete" spam.
Bug 1053657 - Apply minor Media Source Extension spec updates.
Bug 1044498 - Handle overlapped SourceBuffer appends by spinning up a new decoder.  Only implemented for WebM so far.
Bug 1058418 - Logging tweaks.
Bug 1044498 - Save init segment for reuse during overlapped appends.
Bug 1044498 - Fix a bunch of WebM buffered range bugs.