Added APIs to handle initial and final states (such APIs could be extended by the way). Business Process now supports the generation of movements list for a given amount in a given trade phase. This was made by a mixin before (movement generator) but this is unrelated to movemet generators. Appropriate locationis Business Process since this is a core feature.

git-svn-id: https://svn.erp5.org/repos/public/erp5/sandbox/amount_generator@35763 20353a03-c40f-0410-a6d1-a30d3c3de9de