Now, users can set content type explicitly for their files in a number of ways, or rely on automatic file-extension content types. Proxied files default to automatic file-extension content types, but then fall back to the content type of the resource they proxy to. There is also a bug fixed around correctly setting content type inside send_file. Fixes#821.
This allows users to use proxy directly instead of page to create dynamic pages, and improves performance of dynamic pages for sites that create many proxies. It also allows people to use locals instead of instance variables, which are better for partials and reduce the risk of overwriting Middleman settings.