update information hierarchy on webpage

[samccone]

Above the "fold"

• link to the docs hosted on the site
• a link to guides
• how to get the code (direct download + install through bower)
• (as a note the design should be able to work without the link to the docs / guides since they are still a work in progress)

New things

• a style guide for tutorials (see how http://emberjs.com/ and http://docs.angularjs.org/tutorial does it)
• a style guide for the doc pages (see http://underscorejs.org/ and http://roots.readthedocs.org/en/latest/extensions.html#file-sorting)