Fix several bugs wrt extracting messages from js. Also extract title and shorttitle-attributes. Don't extract empty strings.

git-svn-id: https://svn.code.sf.net/p/rkward/code@4988 7936002b-cd1d-0410-9ce3-d7ebf93b5162
Properly deal with the various quoting chars in js message extraction

git-svn-id: https://svn.code.sf.net/p/rkward/code@4989 7936002b-cd1d-0410-9ce3-d7ebf93b5162