Feature/configurable build directory

I find it useful to specify the target directory for the build artefacts. I've added an option, exposed as chain-able method on the builder that can be called in the weyland-config.js file.

Not sure what your plan is for documentation so I have added an md file under a new /docs directory. Should be compatible with the main website if you're continuing with http://docpad.org/

Weyland is a great addition to the Durandal framework, thanks for getting it out there.