Added "elements" and "events" attributes inheritance

I suggest merging parent events and elements with the child ones in Spine controller.
Let me show you how it will work:
```coffeescript
class ParentContoller extends Spine.Controller
  elements:
    '.parent-1': 'el_1'
    '.parent-2': 'el_2'

class ChildController extends ParentContoller
  elements:
    '.child-2': 'el_2'
    '.child-3': 'el_3'

child = new ChildController()

child.el_1 # => $('.parent-1') element
child.el_2 # => $('.child-2')  element
child.el_3 # => $('.child-3')  element
```
The same thing with the events.
Any suggestions?