code: function createTask(taskId) {
  	return function (done) {
  		var stream = tasks[taskId].fn(gulp, done);
  		if (stream) {
  			if (stream.on) stream.on('end', done);
  			if (stream.then) stream.then(done);
  		}
  	};
  }
docs: Create a gulp task for the given id.
  
  @param {string} taskId		Task id to lookup in tasks and assign.
  @returns {Function}			The gulp function.