Integrates zrtp4pj ice failure fix.

git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2293 9f815046-5998-e9c0-b7e2-ac03a23edfa4
Connect slot to other calls when in conferencing and disconnect when hold.
Fixes issue 2027.

git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2294 9f815046-5998-e9c0-b7e2-ac03a23edfa4
Default disabled prefs for opus and mpeg4


git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2295 9f815046-5998-e9c0-b7e2-ac03a23edfa4
Add pjsip plugin to manage opus codec RFC (rewrite the 48000/2 into something we can handle).
TBD : make the default opus internal clock rate a setting (currently 16kHz as it's default audio layer value).
Fixes issue 2060.

git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2296 9f815046-5998-e9c0-b7e2-ac03a23edfa4