Result Set Management applied to the user search plugin. This effectively enables users to page through a potentially large number of results.

User search wasn't compliant with XEP-0055 in the basic search (invalid search fields were used). I replaced them.

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/branches/rsm@9169 b35dd754-fafc-0310-a699-88a17e54d16e