- MFC-R2 requires tone signaling that gets screwed sometimes
           if the EC is enabled during call setup.
         - EC is now enabled only when switching to a state requiring
         media (UP and PROGRESS_MEDIA)
         - The logic is aware of EC persist option in Wanpipe
         - Improved logging in ftmod_wanpipe to print EC state on startup

The defaults for these keys are empty.  This change allows them to be
set empty in the XML config without error.

         - Clean up ftdm_channel_set_sig_status locking and sanity checks
         - Set FTDM_CHANNEL_SUSPENDED when delivering FTDM_SIGEVENT_SIGSTATUS changed to SUSPENDED
         - Clear FTDM_CHANNEL_SUSPENDED when delivering FTDM_SIGEVENT_SIGSTATUS changed to UP
         - Update ftmod_r2 to honor local suspend requests when returning from alarm state

fix session timer failure when freeswitch is generating the sdp and there are enough dynamic codecs enabled to conflict with the 2833 pt (4 by default)

Prior to this change, calling flush_inbound_reg with @domain will
reboot all matching devices (if reboot is specified), but will not
actually flush the matching registrations.

         proper alarm handling for R2 calls

add send-presence-on-register (true|false|first-only) param to sofia and api command sofia global debug [presence|sla|none]

add send-presence-on-register (true|false|first-only) param to sofia and api command sofia global debug [presence|sla|none]

- Use the newly introduced FTDM_SPAN_USE_PROCEED_STATE flag and FTDM_CHANNEL_STATE_PROCEED.

- Update ftmod_libpri's state machine table (taken from ftmod_sangoma_isdn).

- Move pri_destroycall() to HANGUP_COMPLETE state.

- Try to get a little bit closer to the ISDN states by using pri_acknowledge() in RINGING,
  pri_progress() in PROGRESS and pri_proceeding() in PROCEED state.

- Go to PROGRESS_MEDIA in on_progress() only if there is inband indication available, go to
  PROGRESS if not.

- Go to RINGING state in on_ringing() and remove PROGRESS_MEDIA check.

NOTE: One libpri error message and a VETO (PROGRESS -> RINGING) warning to investigate,
      but changes seem to work fine nonetheless.

Tested-by: SparFux (#freeswitch / #freeswitch-de  @ irc.freenode.net)
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>