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/
........

Merged revisions 422112 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@422113 65c4cc65-6c06-0410-ace0-fbb531ad65f3