Adding `_layouts/default.html` from `old-master`

```shell
$> mkdir _layouts
$> git checkout old-master -- index.html
$> git mv index.html _layouts/default.html
```
Extracted from `_layouts/default.html`...

Which used to be the `index.html` for the site.
Ripping out everything from the old theme...

And adding [Twitter Bootstrap](http://getbootstrap.com) and [Font Awesome](http://fontawesome.github.io) so that I have pretty links. I guess I should build and ensure that they _are_ pretty. :D
Adding link to Twitter...
Applying the `navbar` styling from Bootstrap...
Exchanging HTML for Markdown...
Snagging my `_posts` from `old-master`...

* `git checkout old-master -- _posts`
Adding the Bootstrap JavaScript components...

Which I didn't end up using after all, but I have them, if I want to use them.
Set `layout` to `default` for all paths...
Add a page that lists all the posts...

Not completely happy with this solution. I'd rather move my "About" content onto another page and feature my "Posts" content on the landing page... But right now I don't really have a lot of that to feature.