Use Jekyll

Rather than try to maintain the site as bespoke HTML by hand, leverage the power of Jekyll for some sanity. This does a few things:

* Move header to a template, so we're not copying and pasting and updating lots of files each time we make a change
* Use markdown to author content, rather than HTML, which is much, much more accessible to non-coders
* Pretty permalinks (e.g., `/events` rather than `/events.html`)
* More flexibility down the line, e.g., if we want to have a blog or post updates
* Dat SEO

Despite all this awesome, awesome power under the hood, and the ability to significantly simplify our authoring and publishing workflows, the output should be virtually identical.

## Before (:-1:)

![screen shot 2013-10-06 at 2 01 42 pm](https://f.cloud.github.com/assets/282759/1277177/69f0c1ce-2eb1-11e3-944f-224664496f5f.png)

## After (:sparkles:)

![screen shot 2013-10-06 at 2 01 29 pm](https://f.cloud.github.com/assets/282759/1277179/6ea38986-2eb1-11e3-801a-fcfb8b0d8777.png)

## Same output

![screen shot 2013-10-06 at 2 05 57 pm](https://f.cloud.github.com/assets/282759/1277184/fcce6ab4-2eb1-11e3-81cf-c5fcb8368dcf.png)