Port 18003 was chosen at random, but the point is not to use the same
port as PS itself is running on.
This might not be the best approach, but it probably at least beats
running it on the port in config.js and conflicting with an active
PS process.
- Streams are merged to make sure that all errors and warnings are reported.
- Adds dev dependencies: `merge-stream` and `lazypipe`.
- Tracks a fork of `gulp-jshint` to fix https://github.com/spalger/gulp-jshint/issues/88
