Adding in new containers, rows, and columns

For the 3.0-wip branch:

Making the layout work: removing old

This could be played with more in the future, here I just used...

```html
<div class="col col-lg-8">
...
</div>
```

In the future we could replace `lg` with `sm`


Another solution:

Bootstrap's new way of making columns of existing content...

```css
.wrapper {
  .make-row();
}
.content-main {
  .make-column(8);
}
.content-secondary {
  .make-column(3);
  .make-column-offset(1);
}
```

This solution is worth thinking about, but it would require editing/adding of the core bootstrap files.