Build: Rearrange grunt/npm tasks into a build/dist/test pattern

Ref 76df9e4e389d80bff410a9e5f08b848de1d21a2f
Ref https://github.com/jquery/jquery/pull/1949#discussion_r22042517
I use msysgit and bash on Windows, can't imagine getting work done without it. Even if our own stuff works I'd be concerned that something would be amiss in the 27-bazillion levels of npm dependencies below us. However, we pulled out the README instructions for installing msysgit a while back and nobody has come in to say they can't get things up and running on Windows. Not sure what that means, maybe I'm the last Windows user.