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.

FS-5025 Added user/group/domain merge of param/var before calling vm delivery allowing to have variable or param value set at the domain or group level

FS-4916 added beep real beep instead of DTMF, and fixed hangup before end of greeting. I hate the world and the world hate me

mod_voicemail_ivr: Added the new param for API vm_fsdb_pref_greeting_get WARNING, you must add it to the config or else module will complain of missing value... With the new API, it will now playback the greeting when setting it.  Will need to figure out a better way to deal with api being added in the future...  Add support to auto start new message playback and made it default in the config file.
mod_voicemail_ivr phrases : make value = 0 as plural (0 messages).  Don't tell the option for new message if no new message present.  Changes a few default key to match more closely mod_voicemail key settings.