[voicecall] Store the incoming/outgoing state when the call begins.

Otherwise the state is lost when the call is ended and we need it
when saving call counters.
Merge pull request #45 from martinjones/jb14481

[voicecall] Store the incoming/outgoing state when the call begins.
[ngf] Use play.mode=short for subsequent incoming calls.

When one (or more) call is active, new incoming calls shouldn't play the
full ringtone but less intrusive one instead.
Merge pull request #46 from jusa/second-ringtone

[ngf] Use play.mode=short for subsequent incoming calls.