Adding a new option to Chanspy(). The 'd' option allows for the spy to

press DTMF digits to switch between spying modes. Pressing 4 activates spy mode,
pressing 5 activates whisper mode, and pressing 6 activates barge mode. Use of
this feature overrides the normal operation of DTMF numbers. 

This feature is courtesy of Switchvox.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@116522 65c4cc65-6c06-0410-ace0-fbb531ad65f3