Update sounds files.

Update sounds files.

* Add additional sounds prompts for say_enumeration
* Update the English conference sounds prompts so they are better
  quality and all sound more consistent
* Clean up the core-sounds-XX.txt and extra-sounds-XX.txt files to
  include all present sound files

Both core (en, fr, es) and extra (en, fr) sounds files have been updated.

(closes issue #16200)
Reported by: murf

(closes issue #17137)
Reported by: lmadsen

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@259526 65c4cc65-6c06-0410-ace0-fbb531ad65f3