Display codes using keyboard

Found this through [sidebar.io][1], and thought it could do with some keyboard-interactivity, so I plopped it in.

Instead of duplicating the code between the click and key press events, I refactored it out into it's own function. I briefly tried to add it in and match the existing style (as a function attached to $), but it would hang my browser, so I had to put it outside of jQuery, all by itself.

I also added in some CSS to prevent text in #keyboard and #codebox from being selected. I wasn't able to actually compile the SCSS, so I added it into the .css file (and the .scss file, but I haven't tested that) and it all works sweet.

I gave it a quick test through and everything look fine, but let me know if I've missed anything!

[1]: http://sidebar.io