Remove requirejs, replace with browserify

The concrete task is to figure out where each of the dependencies are being used and replace them with `require('name-of-module-here')`. That also requires figuring out which of the modules needs to be registered as an external module with browserify so it can be `require`d outside of the build process. For local, non-vendored modules (basically anything with a relative path, like "./utils") this also involves giving it an external identifier so it can be required