Add debug flag so skinny debug will show information about packets.

We dont want to scare users with this, so we added a devmode compile flag

(closes issue #13952)
Reported by: wedhorn
Patches:
      packetdebug3.diff uploaded by wedhorn (license 30)
Tested by: mvanbaak, wedhorn


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@160938 65c4cc65-6c06-0410-ace0-fbb531ad65f3