CallerID: Fix parsing of malformed callerid

This allows the callerid parsing function to handle malformed input
strings and strings containing escaped and unescaped double quotes.
This also adds a unittest to cover many of the cases where the parsing
algorithm previously failed.

Review: https://reviewboard.asterisk.org/r/3923/


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/1.8@422112 f38db490-d61c-443f-a65b-d21fe96a405b