Add commandline tool for doing CLI commands through AMI (instead of using asterisk -rx)

(closes issue #12389)
 Reported by: davevg
 Patches: 
       astcli uploaded by davevg (license 209)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@113559 65c4cc65-6c06-0410-ace0-fbb531ad65f3