Merge bug 1483 -- advanced voicemail options

apps/app_voicemail.c

configs/voicemail.conf.sample

say.c

sounds.txt

sounds/vm-advopts.gsm

sounds/vm-calldiffnum.gsm

sounds/vm-dialout.gsm

sounds/vm-enter-num-to-call.gsm

sounds/vm-from-extension.gsm

sounds/vm-from-phonenumber.gsm

sounds/vm-from.gsm

sounds/vm-nobox.gsm

sounds/vm-nonumber.gsm

sounds/vm-num-i-have.gsm

sounds/vm-reachoper.gsm

sounds/vm-review.gsm

sounds/vm-star-cancel.gsm

sounds/vm-starmain.gsm

sounds/vm-then-pound.gsm

sounds/vm-tocallback.gsm