* added support for PID export/import to identify bridging in misdn_call already

* fixed a few inband Alerting issues, sometimes we need to create alerting, some
times it's inband
* beautified the state debugging of misdn_hangup
* removed "real"  bchannel activating/deactivating in chan_misdn.c
* fixed "round_robin" bug when there's only 1 port
* added more informative prints when channel could not be created
* changed some warnings to notices
* reworked the whole bchannel state machine stuff, 
  it is now like in the examples of mISDNuser and therefore a lot easier, 
  and it is now harder to create bugs
* bchannel_activate/deactivate is now only called in setup/cleanup bc, 
  they may merge sometime
* it is very important to setup/cleanup the bchannels under the correct 
  conditions, especially in the NT Side we can only setup the bchannels 
  when we send a Message! 
  In the TE side we can only setup the bchannel when we received the channel 
  of course
	      


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@35241 65c4cc65-6c06-0410-ace0-fbb531ad65f3