[voicecall] Set organization name and application name.

This makes QSettings work out of the box.
[voicecall] Keep counter statistics on incoming and outgoing call times.

Provide these over the VoiceCallManager DBus interface, and provide a method to
reset counter statistics also.

This is useful for a user interface to show how much time has been spent on
calls.
Merge pull request #14 from rburchell/master

Keep counter statistics on call times