text and spacer components

[terrencewwong]

I moved the css files to the directory css and now src is being used for the components. The reason I did this is because this is the convention for JS projects.

I also have some questions:

1. I made the Text component a styled.span. This isn't quite the same API that you had before since the size-0, size-1, etc. classes could be used on any type of element. What happens if a user wants a p that has a certain text style. Right now you would need to create a new component that composes p with a Text. So something like

<p><Text size='size1'>{ children }</Text></p>

I think this should be ok, what do you think?

2. Likewise, I made the Spacer a styled.div