Update Jitsi features.

wiki/src/todo/VoIP_support.mdwn

 [[!tag todo/easy]]
 
-[[!taglink todo/research]] if VoIP can be usable in the context of Tails.
+We need to [[!taglink todo/research]] how VoIP can be usable in the
+context of Tails.
 
 Preliminary testing showed
 [OnionCat](http://www.cypherpunk.at/onioncat/) +
@@ -120,6 +121,8 @@ Jitsi (SIP Communicator)
 - supports IPv6, SIP, XMPP
 - supports zRTP for key negotiation, SRTP for voice encryption, and
   TLS for signaling encryption
+- supports audio SIP and XMPP conference calls; what conferencing protocol?
+- supports OTR for text IM
 - reported to work over Tor
 
 Twinkle