MPVideos: Restore compatbility with MediaPortal 1.2
Configurator: Log unhandled exceptions
MetaService: Publish empty strings instead of null over Zeroconf

This fixes a NullReferenceException in DataFromTXTRecordDictionary.
WSS: Reload MediaInfo when the source file changes
WSS: Improve error handling in XmlCache

Also rename the cache file, as we use a new format now. This avoids a logged exceptions
for all people who upgrade from the previous version.
Merge tag 'v0.5.3'

MPExtended v0.5.3
Configurator: Disallow creating duplicate usernames
Configurator: Fix crash when there are duplicate accounts
MPTVSeries: Fix wrong id returned from episode search
Configurator: Also export WebMediaPortal.xml with logs
Streaming: If there is a recording thumbnail image file in the recording folder, use that instead of FFMpeg extraction.
TAS: Use same workflow as MP and SetupTv when deleting a schedule

The existing workflow didn't make any sense at all.
Merge branch 'alternative-mediainfo-fix' into release-0.5
WebMP: Add CSS class to active item in the menu
WebMP: Split recordings away from the TelevisionController
WebMP: Also show "File inaccessible" for recordings
MAS: Add a Watched field to WebMovieBasic
WSS: Add "Interlaced" field to WebMediaInfo (fixes #302)
WebMP: Indicate interlacing in quality field
WebMP: Hide system information when loading it fails (fixes #375)

This avoids showing a system with not-operational performance counters as
idle, and also reduces the number of bugreports: nobody will notice it doesn't
work. It's not an important feature anyway.