Merge in patch for #13454. Includes CallRereouting dialplan application,...

Merge in patch for #13454.  Includes CallRereouting dialplan application, option for discard of remote hold messages, and using the alternate logical channel mapping in Q.SIG instead of the default physical channel mapping.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@150640 65c4cc65-6c06-0410-ace0-fbb531ad65f3