riched20: Add IOleWindow interface support for IOleClientSite.
riched20: Implement IOleWindow::GetWindow.
riched20: Add IOleInPlaceSite interface support for IOleClientSite.
riched20: Add IOleInPlaceFrame interface support for IOleClientSite.
riched20: Implement IOleInPlaceSite::GetWindowContext.
riched20: Add IOleInPlaceUIWindow interface support for IOleClientSite.