Unify gateway printing between 'sofia xmlstatus gateway' and 'sofia xmlstatus gateway <gatewayname>'

mod_callcenter: You can now allow caller that have hangup before agent answer to call back and resume their previous position.

mod_callcenter: Default the level to 0 since the new tier system will wait x second at level 1... just level 0 that will ring agent right away (if set to do so)

mod_callcenter: Add tiers rules before jumping to a different level.  Also added support for dial-in agent.

"skinny profile internal device <tab>" now works

Thanks to Sergio