This change allows us to pass any number of additional properties to embedPC(), which in turn can override properties contained in the XML file; the only property overrides currently supported are 'state' (which overrides any 'state' property set in the XML's <computer> element) and 'automount' (which overrides any 'automount' property set in the XML's <fdc> element). The goal is to make it easier to reuse XML machine definitions, by allowing commonly altered component attributes to be overridden.
