This commit impacts the whole structure app, because we now have
nested Fragments. To keep retro-compatibility, we switched from normal
Fragment to Fragment from the support library.

    - one liner bug in call UI

There is still a bug on incoming calls when buiding for android

Ringtones are routed to speakers for incoming calls

This is the first and very basic audio rerouting imp.
Corner cases needs to be treated

This commit also activates the DTMF route type (SIP or RTP)