Use Jekyll and Grunt to avoid GitHub API calls

[gregoryjscott]

I'm not sure I even like this idea but it was an interesting experiment so I thought I would at least share it. This would fix #19. You can view the result here.

This switches the site to use Jekyll and adds a custom Jekyll plugin that generates a data.js file that contains all the geojson data. The index.html file references data.js. This works great, however GitHub doesn't allow custom Jekyll plugins in GitHub pages (using GitHub's built in support for Jekyll) so we're stuck with generating the content first and then pushing to the gh-pages branch. So, I added Grunt and the grunt-gh-pages plugin to automate that part.

To get this to work right, we'd need to set the default branch back to master and do PRs on master. The deployments steps would be:

1. Merge feature branch to master.
2. Run jekyll build.
3. Run grunt gh-pages.

The last two steps could be setup in Travis so that we'd only need to merge PRs to master and everything else would be automated.

Tasks

• Discuss whether this is a good idea or not
• Revert gregoryjscott@31b679a
• Set master as default branch
• Redo this PR against master?
• Update README with change to using master branch
• Update README with instructions on how to use Jekyll and Grunt (for developers)
• Setup Travis to do the Jekyll and Grunt steps