added clipping functionality to containers. Currently, the clipping function can only be applied to layers and groups. The clipping region is also subject to the containers transforms, which means that you can also create transformed clipping regions.

src/Canvas.js

@@ -204,6 +204,15 @@
                 var t = no.getTransform(), m = t.getMatrix();
                 context.transform(m[0], m[1], m[2], m[3], m[4], m[5]);
             }, true);
+        },
+        _clip: function(container) {
+            var context = this.getContext(); 
+            context.save();
+            this._applyAncestorTransforms(container);
+            context.beginPath(); 
+            container.getClipFunc()(this);
+            context.clip();
+            context.setTransform(1, 0, 0, 1, 0, 0);
         }
     };