Make Menu apply styling to top-level div; position same

In the interest of controlling placement of the menu, styling supplied
to menu is now applied to the top-level div.

The top-level div is also styled `position: relative;` to fix placement
issues, and the activating menu button now closes the menu when pressed
if its active to work around yet more bugs due to bad
getBoundingClientRect.

Fix #143.

src/Material/Menu.elm

@@ -540,14 +540,16 @@ view lift model properties items =
     itemSummaries =
       List.map (Options.collect defaultItemConfig << .options) items
   in
-    div
+    Options.apply summary div
+      ( css "position" "relative" :: properties)
       []
       [ styled button
           [ cs "mdl-button"
           , cs "mdl-js-button"
           , cs "mdl-button--icon"
           , attribute (onKeyDown (Key itemSummaries)) `when` isActive model
           , attribute (onClick Geometry.decode (Open)) `when` (model.animationState /= Opened)
+          , attribute (Html.Events.onClick Close) `when` isActive model
           ]
           [ Icon.view config.icon
             [ cs "material-icons"