Small mistake in wiki page

In the [quick start](https://github.com/ademilter/bricklayer/wiki/Quick-Start) page, there's an example that shows the following CSS:

```
@media screen and (min-width: 1200px) {
...
}
@media screen and (min-width: 768px) {
...
}
```

The order of these two rules should be reversed. The way it is now, a page with width > 1200 will actually use the 768 rule because it will overwrite the other one because it's defined later.