tweaked spacing rules for row elemens holding child-containers in sequence block containers.
unset default values for various prototype properties.
added proper instance variable initialization in course repo constructor.
added attribute for storing children. fleshed out delete method.
passing parent sequence block to new sequence blocks during creation.
moved base object collection and sequence block model collection into the ilios.cim.model namespace. renamed collection to the more precise map.
removed obsolete property _parentcnumber and its getter method.
implemented client-side sequence block model/view removal after a successful delete event was fired.