Better parsing for the "register" line

Allows characters that are otherwise used as delimiters to be used within
certain fields (like the secret).
(closes issue #15008, closes issue #15672)
 Reported by: tilghman
 Patches: 
       20090818__issue15008.diff.txt uploaded by tilghman (license 14)
 Tested by: lmadsen, tilghman


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@213098 65c4cc65-6c06-0410-ace0-fbb531ad65f3