Continuation of support for Rose import of controlled units:

umbrello/import_rose.{h,cpp}
- At function loadFromMDL change argument "bool requireDesign" into
"UMLPackage *parentPkg" defaulting to NULL. Pass parentPkg into call to
petalTree2Uml.

umbrello/petaltree2uml.{h,cpp}
- In function handleControlledUnit pass parentPkg into call to
loadFromMDL.
- At function petalTree2Uml change argument "bool requireDesign" into
"UMLPackage *parentPkg" defaulting to NULL. If parentPkg is non NULL then
create an UMLObject::ot_Package with root->initialArgs()[1] as name and
parentPkg as parent. Reassign parentPkg from the object created, and
pass parentPkg into call to umbrellify.