Use `window` instead of `global`

By directly using `window` instead of `global` we can have browserify
skip some expensive parsing to figure out if it has to shim `global` to
be `window`.
Change build file location

We don't want to build directly to "public/javascripts" because there's a
grunt task that lints all the files in there and it *really* hates
the browserified files. Instead we're gonna build to "public/build" and
ignore everything in that subdirectory.
Remove requirejs related config, files.