Merge in last round of spy fixes. This should hopefully eliminate all the issues...

Merge in last round of spy fixes. This should hopefully eliminate all the issues people have been seeing by distinctly separating what each component (core/spy) is responsible for. Core is responsible for adding a spy to a channel, feeding frames to the spy, removing the spy from a channel, and telling the spy to stop. Spy is responsible for reading frames in, and cleaning up after itself.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.2@42054 65c4cc65-6c06-0410-ace0-fbb531ad65f3