adding titles and summaries to social media share links

I added parameters into the links instead of using Open Graph tags (og tags) as discussed with Dak. OG tags give us more control over what displays when shared, especially in Twitter. But, this is still a big improvement over what we have now.
It does not appear this will update the OpenGraph tags if the abstract changes.  It should update the tags (without re-rendering the entire view) on `change:abstract` or `change:currentPage.abstract`.