Add getStore function to RiotControl

[wind13]

Sometime we need to get store from RiotControl at another page/view, what we did it now is like this:

            RiotControl._stores[0].load();

That will be better if we can use it like this:

            RiotControl.getStore("TodoStore").load();

[wind13]

And all the demos should be refactor then.

[jimsparkman]

I'm not ignoring this, I just haven't had time to experiment with it yet. Also looking at a major restructuring #23.