FS-3095 --comment-only This patch removes the existing conference transfer function and replaces it using the core transfer it also introduces a new tracking method where the same conference id is reserved for a particular member for the lifetime of the call allowing a user to transfer in and out of conferences and ivr and bridges etc and retain the same member id for the duration of that call

Unbreaking make -jX parallel builds...
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

FS-3194 see comitted patch. I made the function assert rather than tolerate NULL and fixed the imporper usage.

ringback tones defs - remove redundant second 0Hz freq where applicable, add some more complex examples

mod_callcenter: Temporary fix for some race condition with loopback agent.  Need to find the root cause of this problem

mod_sofia: Correct a problem where restarting profile would cause some profile hash entry to remain.