Fix bug that caused "Custom search query" to disappear for video items

Fixes #1696
Pull XMP fwd
Create video metadata menu items on demand
Fix some memory leaks
Fix some additional issues in metadata item popup
Add new configure option --enable-bughunt

It enables a few things that makes it easier to find issues with valgrind
Fix bug in bzip2 build helper
Get Danish translation back
rpi: Rework main loop and add CEC support
rpi: Improve video playback (Fix HLS streaming, fix play/pause)
upnp: Include video playback URL in canonical URL

Fixes problem with UPNP servers that just give sequential numbers to
directory items. If just using the URL items would be confused with
other items if video are removed from the directory

Fixes #1697
Fix bug that caused incorrect restart position in continious playback mode

Problem was that timestamp got fed back from previous video item into
the playback pipeline