Relocate the path in Site.__init__

Allows to deploy from anywhere in the repo
Support optimize for deploy
Memoize .pages() and .static()

Maybe an issue if we built multiproc, but we'll handle this another day
Added fingerprinting and optimization of CSS/JS

Adds an optional dependency on closure-compiler for JS and one
yuicompressor for CSS

Need to enable YUI for JS too!
Added an utility method in Site for statics

This method helps locate where a static eventually is built to, which
can be "unexpected" due to fingerprinting