* Add a deleted messages option to voicemail.
Messages are only deleted after a certain amount of time instead of immediately.
The queue can be turned off or on with the default setting "use_deletion_queue" in the "voicemail" category.
Changed deleted phrase and added a deleted messages count phrase
Added a program to delete messages that are due for deletion. Also small changes to phrases.
* Added a remove_deleted_messages function that runs on voicemail main menu log in. With this method, the deletion queue is handled per mailbox vs system-wide as in the cron-triggered script. It also allows us to adjust the retention hours on a per-domain basis.
