- use libxml2 to manage cache
- add set/unset previously verified sas flag management interface
- clean debug code

+ remove peerSSRC from context as it was useless
+ get correct test patterns for parser/builder

Add confirm2 repetition management when in final state

+ srtp secrets send first receiver then sender to the client to
meet protocol requirement allowing optional sending of conf2ACK packet
+ move packet check in processMessage function
to prepare for ping and error zrtp message processing

And bug fixes
First functional version(not fully compliant with the RFC yet)

Not functionnal yet

Non functional