GitLab

 - Simplify update of missed calls number.
 - Remove useless entries in context menu of contact list.
 - Change icons to clear call history and chat message list.

quality_reporting_tester.c: remove test for Adaptive Algorithm part of reports since it cannot be done reliably

Make volume control buttons non-sensitive when it is not possible to get volume gain from the sound card

* use the "linphone-start-chat" icon
* factorisation of the code managing the display of header tabs

Fix crash in quality reporting when call with audio, video and text + fix future index out of bound issue (if main stream index > 3)