set rtp stack into optimal mode for transferring data during fax situations (that does not mean we support the idea of audio fax over ip......)

Make sure the received DTMF duration is initialsed at the beginning, and if the realtime calllback is set or altered during operation of the detector.

FS-3735 that is a resonable figure, if that works we can set it to this. can we close out this bounty then?

comment out unused variable to satisfy build when compiling under core CFLAGS with warnings as errors

Add T31 modem support to mod_spandsp - similar to iaxmodem only wired into FS.  Also merge configs into single spandsp.conf.xml --see in tree example--

poor detection.
Fixes to how timezones are handled for FAX page headers.
Various cleanups of the spandsp headers.