Use the model as context when calling methods on objects

@@ -85,6 +85,13 @@ describe('Rivets.Binding', function() {
       expect(binding.routine).toHaveBeenCalledWith(el, 'awesome sweater');
     });
 
+    it('calls methods with the object as context', function() {
+      binding.model = {foo: 'bar'};
+      spyOn(binding, 'routine');
+      binding.set(function() { return this.foo; });
+      expect(binding.routine).toHaveBeenCalledWith(el, binding.model.foo);
+    });
+
     describe('on an event binding', function() {
       beforeEach(function() {
         binding.options.special = 'event';

@@ -48,7 +48,7 @@ class Rivets.Binding
       @routine @el, value, @currentListener
       @currentListener = value
     else
-      value = value() if value instanceof Function
+      value = value.call(@model) if value instanceof Function
       @routine @el, value
 
   # Subscribes to the model for changes at the specified keypath. Bi-directional