[rbp] fixed compile
[airplay] - handle empty session ids from itunes
[airplay] - fix the playtime - itunes is very picky about the formatting here
[airplay] - refactor the playstate announcement by using the IAnnouncer interface
- also adapt to some new findings on revers engineering itunes airplay traffic (add sessioncounter to reverse event and fix http request formatting)
- fixes #14191
[airplay/airtunes] - backup volume on airplay/airtunes volume change and restore it on playback stop