Sébastien Blin authored Oct 25, 2017 and Adrien Béraud committed Nov 01, 2017

+ Remove the "Conversation started" message
+ Add "Contact added", "Invitation received", "Invitation accepted"
messages
+ Improve CALL messages.

Note: a behavior has changed. Now, if we clear the history, all
interactions will be removed.

Change-Id: I0bf9320c6aecaf45dbfd0fd8de738f583be7e817