Commited Tue. October 16, 2007 at 01:33:58 PM EDT
correcting issues regarding polymorphic assignment
* making ObjectBase::operator=(ObjectBase) protected to avoid inadvertent usage
* introducing ObjectBase::set(ObjectBase) for explicit polymorphic assignment, based on loadXMLNode() to respect loadSavePolicy settings
* PrimitiveBase::operator= is now virtual to allow easy primitive-specific polymorphism
