Fix the <partial> handler to handle asynchronous partial's
Reimplement as Mahabhuta tags
Code cleanup
Fix oembedRender so it properly detects missing arguments -- AND -- allows the template to be NULL, in which case it returns the HTML provided by oEmbed
New file
Pin Cheerio to v0.15 because of a regression in 0.16 - https://github.com/cheeriojs/cheerio/issues/460