This begins the initial implementation of a unified QueryInterface on the dispex. There's a couple of hacks used to make the conversion split up easier, but they're all resolved within this MR.
-- v3: mshtml: Trace the object name in dispex methods. mshtml: Use query_interface in the dispex vtbl for XMLHttpRequest. mshtml: Use query_interface in the dispex vtbl for inner windows. mshtml: Introduce query_interface in dispex vtbl and use it for DOM Nodes. mshtml: Return interface directly from node vtbl's QI instead of HRESULT, mshtml: Expose an EventTarget interface on the outer window for events'