Add atom.xml template for generating RSS feed
Reformat footer.html with all spaces

It was mixed spaces/tabs.
Enable configurable Google Analytics tracking

By setting `ga_tracking_id` and `ga_domain` in _config.yml, the tracking
code in the footer is generated with the proper configuration. If either
setting is omitted, the Google Analytics block is not rendered.
Merge pull request #5 from ssorallen/master

RSS feed and Configurable Google Analytics
Use 2 spaces for indentation in post.html

Other files use 2 spaces, standardize here too.
Add schema.org BlogPosting markup to blog posts

* Wrap date in `<time>` element to provide ISO8601 timestamp
* Wrap body in `<div>` to mark it as the article's body
Convert indentation in index.html to 2 spaces

2 spaces seems to be the convention in other files.
Add schema.org BlogPosting markup to posting index

* Replaced `<span>` element with `<time>` for publish date
Merge pull request #6 from ssorallen/master

schema.org BlogPosting markup
Merge branch 'master' into gh-pages