add object/functions and object/bindAll

I'm kinda tired of doing:

```js
this._pickDateOnClick = bind(this._pickDateOnClick, this);
this._openOnEvent = bind(this._openOnEvent, this);
this._closeOnEvent = bind(this._closeOnEvent, this);
this._scrollNextOnEvent = bind(this._scrollNextOnEvent, this);
this._scrollPrevOnEvent = bind(this._scrollPrevOnEvent, this);
```

to be able to attach listeners to mouse/keyboard events. This would be clearer/simpler:

```js
bindAll(this, '_pickDateOnClick', '_openOnEvent', '_closeOnEvent',
    '_scrollNextOnEvent', '_scrollPrevOnEvent');
```