socketlock testing changes
disabled faulty VDR GetSignalQuality() / GetSignalStrength() functions

using these functions causes freezes on Live TV when the channel scanner
times out on tuning (applies only to systems with more than 1 device)
streaminfo: unified streaminfo handling

- same stream data for demuxers and channelcache
- speedup of channels switching (with warm caches)
streaminfo: removed sendStreamInfo()
streaminfo: serialize stream information and persist channel cache
streaminfo: write channel cache in temp file before overwriting old cache file
protocol version 5

- also supports version 4
- added missing values from the XVDR_STREAM_CONTENTINFO message
  to XVDR_STREAM_CHANGE
- removed XVDR_STREAM_CONTENTINFO message
- added duration to XVDR_STREAM_MUXPKT
fixed info log entry