add 'share on fb'/'share on twitter' links to document page

[jameslaneconkling]

these already exist in the footer, but aren't very prominent there. can we move them to the top of the page, maybe directly below the header? or somewhere else that is visible but doesn't throw off the flow of the page.

[jameslaneconkling]

re-assigning this to myself. need to rethink social media buttons (probably move out of the footer)