Modifying js-builder and testing it locally with another package (before npm publish)
can be a little "tricky" when that other package also uses gulp for building. npm linking
the js-builder package into the other package is not going to be enough.
For that reason, I (Tom Fennelly) have a local npm linked copy of gulp. Then, I npm link gulp
in both js-builder and the package I'm using to test.
(Note: this assumes you already have gulp installed globally i.e. npm install -g gulp)