ability to seek back where phone rang the first time

Changed behavior for incomming telefon call:

1. Telefon rings -> xbmc shows message box with phone number (internaly the time stamp of movie is stored).
2. If Telefon is picked up -> xbmc is set to puse (you decide if you answer the phone :))
3. If telefon call is finisched -> xbmc jumps to time stamp of first telefon ring and starts playing again.

In addition xbmc should not go to "play" if the video was manually paused and a phone call is incomming.