Scribble integration

Don't freak out about the file/commit count - this is all separate to the code itself. And it's mostly noise which i'll nuke in the future.

The important thing: http://shiftkey.github.io/MahApps.Metro/

That's the new site.

So tell me:

 - What's missing?
 - What's not good?

Things like performance and optimisations can wait (unless you think they're *really* important) - I want to focus on the content for now.

The whole **Contribute** section is new content, so check that out.

I want to get this to a point where I can push it live, so I'm more focusing on bring over the existing content and updating it. It can be a bit rough initially, but I'd like to get this integrated so that others can contribute documentation too.

And yeah, it's not responsive at all. It's on my list. But content first.

Oh yeah, and that **scribble** thing is a project I've been working on over the past while. I'll explain it in more detail another time, but you can read up about it here: http://shiftkey.github.io/scribble/

I'm gonna keep editing stuff in the meantime. Feel free to ask questions about whatever's in here and I'll try to explain things further.