Add support for default "say mode" (whether to use the "old" method or "new"...

Add support for default "say mode" (whether to use the "old" method or "new" method.  "new" method being config file)
Add support for autocomplete of "say load" CLI command.

Patch by IgorG
(closes issue #10243)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@76216 65c4cc65-6c06-0410-ace0-fbb531ad65f3