Don't let button controls interfer with handlers.

This change involves removal of the map's eventsDiv and introduces an OpenLayers.Events.buttonclick component that adds a buttonclick event which makes sure that only events that are not related to clicking a button propagate. This allows button controls to be on the map's viewPortDiv again.

lib/OpenLayers/Handler/Hover.js

@@ -107,7 +107,7 @@ OpenLayers.Handler.Hover = OpenLayers.Class(OpenLayers.Handler, {
      * {Boolean} Continue propagating this event.
      */
     mouseout: function(evt) {
-        if (OpenLayers.Util.mouseLeft(evt, this.map.eventsDiv)) {
+        if (OpenLayers.Util.mouseLeft(evt, this.map.viewPortDiv)) {
             this.clearTimer();
             this.callback('move', [evt]);
         }