needed for inheritance of testWorkflowMixin class

add workflow method to get transitions list and by id
  getTransitionValueList
  getTransitionValueById

change and rename method to return a dict
create new method to return state object for a given id

changes were also applied to DC workflow, which should not be changed

rename files my_default_expr.xml to my_default_expression.xml
rename default_expr to default_expression in xml files and scripts

ERP5Workflow: add variable to avoid multiple call to function and remove successive 'if/continue' for readability

ERP5Workflow: revert more changes (some Property Sheets have been moved to erp5_workflow bt5, they are back to product/ERP5/bootstrap)

- erp5_test_workflow
  *  add testWorklowMixin test case for inheritance purpose,
  *  move testWorklist ERP5 test to portal_component

author: Wenjie Zheng