documentation for messages.py

git-svn-id: https://svn.eionet.europa.eu/repositories/Zope/trunk/Products.Reportek@31500 24821446-e7ea-0310-81ac-b189f4507b0b
reorganize api docs page

git-svn-id: https://svn.eionet.europa.eu/repositories/Zope/trunk/Products.Reportek@31501 24821446-e7ea-0310-81ac-b189f4507b0b