Bring Voicetronix driver up to date with current drivers

(closes issue #12084)
 Reported by: mmickan
 Patches: 
       chan_vpb.cc.diff uploaded by mmickan (license 400)
       module.h.diff uploaded by mmickan (license 400)
       vpb.conf.sample uploaded by mmickan (license 400)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@104502 65c4cc65-6c06-0410-ace0-fbb531ad65f3