Added ability to customize which buttons control forward, reverse, pause, and...

Added ability to customize which buttons control forward, reverse, pause, and stop during message playback.
(closes issue 9474, reported and patched by jaroth with modifications by me)



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@72329 65c4cc65-6c06-0410-ace0-fbb531ad65f3