Short summary of changes:
(Massive) rework of the Q.921 layer
Q.931 changes to get BRI PTMP working and cleanups (more to come...)
Add Hi-Layer compat and Progress IE to outgoing SETUP messages
Improve handling of call tear-down in zap_isdn.c
Open ZAP I/O channels after processing the dialplan for incoming calls
Bearer Capability and Channel ID IE handling improved for BRI/PRI and A-law/u-law
...and a lot of other small changes
git-svn-id: http://svn.openzap.org/svn/openzap/trunk@512 a93c3328-9c30-0410-af19-c9cd2b2d52af
