Allow "REMAINDER" to function properly in expressions.

(closes issue #16427)
Reported by: wdoekes
Patches:
      ast16-reminder-remainder.patch uploaded by wdoekes (license 717)
Tested by: wdoekes


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@236713 65c4cc65-6c06-0410-ace0-fbb531ad65f3