Added pretty button styling and organised donor_box contents

### Pretty Buttons
The buttons have been re-styled and also have state effects, such as lightening the background on hover.
![Pretty Buttons](http://i.imgur.com/Dn0Bla9.png)

### Footer
I've compressed the footer height to make it look a little bit tidier and not links stacked up on eachother.
![Footer](http://i.imgur.com/nBtUF50.png)

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Do you want to keep the default buttons or pull any of these changes in separately? I've squashed these two changes into one commit to take less from the tip fund.

So if you only like the buttons, or the footer, let me know and I'll resubmit as individual pushes.