Added a preRender hooks to ListItemView and ContainerView

This allows the user to manipulate the ListItemView and ContainerView before being rendered. 

Example: The user wishes to change the cssClass on a ContainerView in a ListItemView.

```
listItemTemplate = M.ListItemView.design({
    childViews: "myContainer",
    contentBinding: { .. },

    myContainer: M.ContainerView.design({

        // new pre-render logic proposal
        beforeRender: function() {
            if (this.parentView.item.property == YES) {
                this.cssClass = "other-css-class";
            }
        },

        cssClass = "original-css-class"
    })

})
```

Note: please consider opening a discussion on this pull request and improve upon it if deemed incomplete.