Leverage npm scripts instead of requiring gulp to be installed globally. #280
Hi there! I was checking out Bedrock and it struck me that having gulp installed globally is required to get it to work. This PR removes that dependency and might make a little bit easier for people to get going with Bedrock. I've tested this locally on node 8.3 and it works, but maybe give it another spin to be sure! Feel free to decline if there's another reason for having gulp installed globally.