adding other kinds of image (specifically RTP and TCP/TPKT).

FS-5068 --resolve this was an edge case assert in a DNS error.  You may want to check that you have valid DNS servers but this should stop the crash

libzrtp strings are weird, and we were previously misusing the
function zrtp_zstrcpyc.  We can't use ZSTR_GV because it does insane
things and causes an array-bounds warning on gcc 4.7.  So we have to
take matters into our own hands and setup the string correctly and
copy data into it.

Because we were doing it wrong, people would get weird pseudo-random
single-character names for the zrtp cache file, and the file would end
up in the wrong place.  Now that this is fixed, users will need to
locate and move their zrtp cache file to their db_dir and name it
"zrtp.dat" if they wish to keep their current ZRTP cache.

FS-4344 --resolve

mod_voicemail: add extra param inside the MWI event to know if it was fired because of a new message, or other reason

in some T.38 packets from Commetrex and Cisco machines.