mod_sofia: Add a quick fix for basic Polycom presence support.  A more sane solution need to be implemented

add last_bridge_to var to keep uuid of last bridged channel and fix race in show calls on hangup of bypass_media channels

mod_callcenter: Added value busy_delay_time and reject_delay_time so we can wait if those 2 occur (Un registred phone are considered as busy). Add a ready_time epoch time when we can contact an again again, fix ring-all (good this time I hope).

fix 302 to hangup in the two cases where switch_ivr_transfer is used and not in the case when it should carry on and follow the redirect