Builder Prototype

_Note: I'm trying to experiment with Github's "How to use pull requests for internal teams." This feature is nowhere near complete but this way we can try holding the discussion in this thread. For more info, see: http://scottchacon.com/2011/08/31/github-flow.html_

Builder is the core interface that designers will use when building sites/apps with Strummer.

You can see the core definition here: https://github.com/strummer/strummer/blob/builder/builder/README.md

I'll keep working on this pull request/branch, any feedback appreciated.