Bug #1087. Fix wav49 format so it can be played. Make file functions

looking for extension use f->exts instead of f->name.  Fix bug
where error message didn't print file extension. Fix comments in header file.
Everything is completely backwards compatible


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2247 65c4cc65-6c06-0410-ace0-fbb531ad65f3