animate automatic scrolls and don't scroll to border

This adds a subtle animation effect when scrolling to the #scroll__here
behaviour ID. It also adds a 100px offset to make the object not stick
to the browser border.

lib/scripts/behaviour.js

@@ -64,7 +64,9 @@ var dw_behaviour = {
     scrollToMarker: function(){
         var $obj = jQuery('#scroll__here');
         if($obj.length) {
-            $obj[0].scrollIntoView();
+            jQuery('html, body').animate({
+                scrollTop: $obj.offset().top - 100
+            }, 500);
         }
     },