Placeholder method called when indexing a movement.

    It can be overloaded to generate multiple movements 
    from a single one.
    It is used for cataloging a movement multiple time in 
    the movement/stock tables.

    Ex: a movement have multiple destinations.
    asMovementList returns a list a movement context with different 
    single destination.



git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@12466 20353a03-c40f-0410-a6d1-a30d3c3de9de