Improve Facebook Open Graph compliance for sharability

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A report: https://developers.facebook.com/tools/debug/sharing/?q=http://www.nationofmakers.us/
Background and info: https://developers.facebook.com/docs/sharing/webmasters#markup

Courtesy David Brenner in Slackchat. (https://nation-of-makers.slack.com/archives/general/p1480712874002153)

[thejameswilliam]

I added a pull request that adds this stuff for twitter and facebook! Happy to contribute!