Quickly moved core to mixin, added what is needed for new BPM (taken from BPMBuilder.py now in Legacy) and tried to have single code base)

git-svn-id: https://svn.erp5.org/repos/public/erp5/sandbox/amount_generator@37547 20353a03-c40f-0410-a6d1-a30d3c3de9de