- Manage method for clearing old sessions/tokens.

- Improve logging. Make logging API available to DTML/python objects.
	Make logging more generic.

- Setting permissions for dtml methods created inside mysqlUserFolder 
(this is too complicated to be done automatically, it is much easier to
be done manually).

- Token parameters should not be hard coded.

- Database should have informations about user rights to change password,
realname, ...

- MiscData value should be allowed to be any python object (using pickle
mechanism).
