Fix problem with HLS in videosource:{}
Fix crash in SRT files when a subtitle entry contains unparsable tags only

Fixes #1501
Fix a buf that made "Custom query" impossible to erase in the metadata editor
js: Add support in javascript API for binding video metadata to items
glw: Rework syntax of propSorter() so it's much more flexible
Display subtitles in order of preference
js: Add showtime.xmlrpc() for doing XMLRPC requests
Fix missing locking
Add plugin support for subtitles

This also removes built-in support for opensubtitles.
It will be shipped as a plugin instead
changelog fix
js: Fix crash when page model is deleted
Propagate 'title' from videoparams to subtitle scanner
Parse year,season and episode from videoparams

Also pass this information along to subtitle scanner
Invoke sub scanner from RTMP player
Parse 'imdbid' from videoparams
Compute hash for thesubdb.com when playing a video file

Result found in req.subdbhash in addSubtitleProvider()-callbacks
Add memfile:// to VFS that expose raw memory as files
If a downloaded subtitle is a ZIP archive, open it and try to find a subtitle inside
Fix broken seeking in FLAC files

Fixes #1435
configure: Fix some issues with sed