zapit/include/zapit/frontend_c.h: prevent setTsidOnid() to change
current transponder id on locked frontend:
fix case when PiP started while no live channel running (ie playback mode), return to live playback mode
can break running recording
zapit/src/zapit.cpp: there is case when unlocking live playback can fail
due to all frontends busy and zap back to live channel not possible.
Send CZapitClient::EVT_ZAP_FAILED to notify neutrino
gui/infoviewer.cpp: restore channel id in showMovieTitle(),
else infoviewer do not process some events after playback stop
Merge remote-tracking branch 'cool-next-cc/next-cc'