[Hummingbird] Add support for the Beans framework in Hummingbird

Hi guys,
I\'ve been setting up Hummingbird for a client and while most of it\'s working as expected, the one thing that I can\'t seem to get working is the minification.

The clients site is built using the Beans framework, which can be described as Genesis on steroids. It\'s 100% free/GPL and has over 20k developers using it.

It would be really awesome if you guys could hook into the Beans compiler to allow for minification, inlining the css, splitting the compiled css into critical inline and the rest deferred in the footer.

Cheers,
Chris