variation_category is implemented

Do not give conflicting instructions to portal_catalog.

Preserve compatibility with in-zodb worklist cache code, but do not use
*_expression when calling catalog.

These are a bit more complex, there are more to come.

These are the easy uses, there are more to come.

Waiting document onlyoffice conversion error fix

In order to safely use non-XML allowed characters coming from various
sources wrap basestring into xmlrpclib.Binary before sending it to the
server.