rtrees are now created as a constructor

examples/chess/main.js

@@ -1,5 +1,14 @@
 /* main.js – runs the demo with your prototype-based grid */
 
+var rtree = use('rtree')
+
+var mytree = new rtree
+
+mytree.add()
+mytree.kill()
+
+for (var i in mytree) console.log(i)
+
 var moth = use('moth')
 var json = use('json')