This allows us to continue using the Node web server to debug machines that are launched using new YAML-based Markdown machines settings, the most important being 'automount' (otherwise those machines might not be loaded with the correct disks)
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.
