Bug 31300: Modify Tor Launcher so it is compatible with ESR68

Replace some wizard and dialog "on" attributes with event handlers.
Replace the XUL listbox element (which was removed by Mozilla) with
  richlistbox.
Replace the XUL progressmeter element (which was removed by Mozilla) with
  an HTML progress element.
Define our own CSS rules for groupbox elements (Mozilla removed the
  built-in styles).
Fix some minor CSS incompatibilities.