Added multiple scope support in Sortable behavior.
fix deleting related objects

An object that is related to another one where this relation is required is meant to be deleted by Propel to ensure its behavior upon deletion.
If the relation is not required, but the foreign key defines a CASCADE behavior on deletion, the object will also be deleted.
Merge pull request #656 from havvg/feature/delete-object

deleting objects
Merge pull request #616 from marcj/sortable-multi-scopes

Added multiple scope support in Sortable behavior.
Merge 'propel/master' into 'master'