Add recording agent's calls patch. Basically the call starts recording when...

Add recording agent's calls patch. Basically the call starts recording when the agent picks up and the file is stamped with the agent's id and the timestamp. Also optionally a URL link to that file may be inserted in the userfield of the CDR record. By default the recorded file will be mixed if soxmix is available.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2121 65c4cc65-6c06-0410-ace0-fbb531ad65f3