Date/Time tidy up

 - Added date to archive page for each post
 - Added date, tags and comments to blog and article view
 - Changed date_formatted to date_text, which seems to be the new way jekyll does it
 - Tested out excerpt on first blog post, seems to work really well
Centered Footer

As pointed out by @seblis27, made sure that the footer was centered on the page
Added prose.io configuration

As per article here:

http://jake.ginnivan.net/blog/2014/06/10/low-friction-octopress-github-pages-setup/

Added configuration options for using prose.io to create blog posts.