Fix several interrelated issues dealing with the holding bridge technology.

* Added an option flags parameter to interval hooks.  Interval hooks now
can specify if the callback will affect the media path or not.

* Added an option flags parameter to the bridge action custom callback.
The action callback now can specify if the callback will affect the media
path or not.

* Made the holding bridge technology reexamine the participant idle mode
option whenever the entertainment is restarted.

* Fixed app_agent_pool waiting agents needlessly starting and stopping MOH
every second by specifying the heartbeat interval hook as not affecting
the media path.

* Fixed app_agent_pool agent alert from restarting the MOH after the alert
beep.  The agent entertainment is now changed from MOH to silence after
the alert beep.

* Fixed holding bridge technology to defer starting the entertainment.  It
was previously a mixture of immediate and deferred.

* Fixed holding bridge technology to immediately stop the entertainment.
It was previously a mixture of immediate and deferred.  If the channel
left the bridging system, any deferred stopping was discarded before
taking effect.

* Miscellaneous holding bridge technology rework coding improvements.

Review: https://reviewboard.asterisk.org/r/2761/


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@397294 f38db490-d61c-443f-a65b-d21fe96a405b
res_stasis: remove call to missing function control_continue.

In the shuffling around of res_stasis, control_continue was renamed to
stasis_app_control_continue, but the call in res_stasis wasn't updated.
In looking into it, it turns out it wasn't really the right thing to do
in res_stasis anyways.

This patch changes the handling of received a AST_CONTROL_HANGUP frame
to be the same as receiving a NULL frame, and removed the declaration of
control_continue(), since it doesn't exist any more.

(closes issue ASTERISK-22292)
Reported by: Denis Smirnov


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@397295 f38db490-d61c-443f-a65b-d21fe96a405b
ARI: Remove the 'channel:' scheme from endpoint's channel list.

For times when a reference in ARI might be ambiguous, the reference is
built as an URI (such as channel:1376341790.3).

An endpoint's channel list is not ambiguous, and in fact the field is
named 'channel_ids', but it had channel URI's instead of channel id's.
This patch changes the list to be the raw id instead of the URI.

(closes issue ASTERISK-22291)



git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@397297 f38db490-d61c-443f-a65b-d21fe96a405b