freetdm: Fix longstanding minor bug in ftdm_span_send_signal causing dial-regex in Analog modules to not work
         The return status of the signal callback was not being passed to the signaling module delivering the signal

This is configured through 2 new parameters:
ringback-during-collect=yes|no
ringback-file=<wav file path>

You may not want to use this if your E&M lines are connected to traditional phones, otherwise
you will hear ringback tone while pressing digits. This is mostly useful with old switches that do
not provide ringback tone but the user is already done dialing (perhaps the signaling was converted from
ISDN to E&M and the full number was received in a single SETUP message)

Conflicts:
	src/include/switch_core_media.h
	src/mod/endpoints/mod_sofia/sofia_media.c
	src/switch_core_media.c

FS-5530 --resolve this will make it identical to the bridge behaviour even when the bridge in early media begins and now you will explicitly need continue_on_fail=true in this situation to not fail

Fix applied to Punchblock here: https://github.com/adhearsion/punchblock/commit/cef5198e80b60e19fc949b21f6e0dc438cecc5df

FS-5531 --resolve add another optional param to supply flags for either behaviour n for null and b for boolean