Initial update to be compatible with Jekyll 2
Added jekyll-sitemap, jekyll-date-format, and updated gems
No longer including Gemfile.lock. Turns out that was a bad idea.
Merge pull request #1589 from imathis/jekyll-2

Jekyll 2.0 compatability
Replaced date plugin with jekyll-date-format
Removed date plugin, added excerpt separator default
Merge branch 'octopress-source' into source
Yay _data!