Add an 'R' option to Dial which sends ringing until early media has been received.

(closes issue ASTERISK-10487)
Reported by: Gaspar Zoltan
Patches:
	10487.patch uploaded by n8ideas (license 6075)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@401411 65c4cc65-6c06-0410-ace0-fbb531ad65f3