New WorkflowMethod implementation. This new implementation solves most issues which existed previously and related to multiple workflows for a single workflow method ID. It should also be faster but will require some more work so that changes in workflow definition are reflected automatically in workflow methods registration.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@15812 20353a03-c40f-0410-a6d1-a30d3c3de9de