[Jami] Bugs and improvements [Jami Android - 20190317]

[simobb2002]

Hello,

I contact you to report bugs and make suggestions to you : 

 - When i start a video call with a friend, Jami freeze and shutdown... 

My brother have trying and he also has the bug...

 - When i'm on "do not disturb" mode and a friend calls me via Jami, the 
application emits a ringing tone when I have forbidden all sounds....

- During a videocall, the faces are distorted.  I've tried other applications 
and only Jami distorts faces.

- Actually, i can't rename my friends in the app...  It'll be cool to be able 
to do it.

- It would also be great to implement a dark mode

Thank you for this app,

Best Regard,