This is the trunk version of the patch to close

issue 12979. The difference between this and the
1.6.0 and 1.6.1 versions is that this is a much more
invasive change. With this, we completely get rid
of the interfaces list, along with all its helper
functions.

Let me take a moment to say that this change personally
excites me since it may mean huge steps forward regarding
proper lock order in app_queue without having to strew
seemingly unnecessary locks all over the place. It also
results in a huge reduction in lines of code and complexity.
Way to go Brett!

(closes issue #12979)
Reported by: sigxcpu
Patches:
      20080710_issue12979_queue_custom_state_interface_trunk_2.diff uploaded by bbryant (license 36)
Tested by: sigxcpu, putnopvut



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@142146 65c4cc65-6c06-0410-ace0-fbb531ad65f3