Day2 1st cut js

* Authored the models
* Integrated LocalStorage
* Started authoring unit tests 
* Not yet added the capability to add a new todo. You can play with this app by injecting:
```
localStorage.setItem('DoToo.todos', '[{"text": "abc"}, {"text": "hello"}]');
```
I personally prefer the initial syntax as it does not put any global variable (DoToo is the later case). But that's a personal choice.