Added item identity providers and converters
Updating tvdb providers to use item identities
Sort identities by provider order
Properly fill in RegError
fixes #674 - Support converting subtitles to webvtt
Merge branch 'master' of https://github.com/MediaBrowser/MediaBrowser
Support subtitle offset
added IsTextSubtitleStream
chapter downloading fixes
set language on chapter search
update ffmpeg
fix ffmpeg date
Merge pull request #811 from thogil/item_identity_providers_2

Item identity providers
Merge remote-tracking branch 'upstream/master'

Conflicts:
	MediaBrowser.WebDashboard/dashboard-ui/scripts/mediaplayer-video.js