Change #tabLink to .tabLink, added font-family

Hi Danny,

I've made a pull request here of a couple of changes that will help you out quite quickly.

In general, I like the direction you're taking, but there's still a few basics we need to sort out. 

I've made two small changes:

1) Changed the `id="tabLink"` to `class="tabLink"` in the HTML (and `#tabLink` to `.tabLink` in the CSS).
The rule for class vs id is that id's can only exist once on a page, but classes can exist multiple times. As such, a 'tabLink' should always be a class.

There's another reason it's better to use classes for styling, and that's to do with [specificity](http://www.stuffandnonsense.co.uk/archives/css_specificity_wars.html) - using id's makes it harder to extend and override styles later on (that's what the _Cascading_ stands for in CSS). 

Because id's only exist on one element on the page, we do prefer to use them for JavaScript, as it makes it much faster for the browser to get the right element - that's for another day though.

2) I added a `font-family` to the `body` just so I could see how it looked with a sans-serif. I'd suggest you start looking at the font-sizes soon.

A few observations:

When you get a chance, you want to get all `style=""` attributes out of the HTML, and start thinking about your CSS modules (Have you had a chance to look at SMACSS.com yet?).

you gave your heading a class of 'style'. Is that a useful, re-usable name, do you think? with a link with a class of `.tabLink` I know exactly what it's meant to be used for - tab-based links. When I read `h1.style`, I've no idea what it's for!

GitHub should help you merge my changes into your repository, let me know if you get stuck though.