Upgrade ObjectStore to maintain proper ordering of object creation and deletion.  It will call constructors/destructors on Object as appropriate, and will soon have a replaceObject() method to help with that.  ObjectStore changes are managed by changeset IDs now.  Associated cleanups and several bugfixes, including steps toward getting functions to work.
Functions compute their type as soon as we add their '{' child, so we can properly analyze the block's contents.
Poor implementation of assignment (objects and functions) and object/scope cloning