code: function applyListeners(emitter, listeners) {
      Object.keys(listeners).forEach(function(name) {
        emitter.addEventListener(name, listeners[name]);
      });
    }
docs: Applies an object of listeners to an emitter.
  
  Example:
  
  applyListeners(someDivElement, {
  mousedown: someFunc1,
  mousemove: someFunc2,
  mouseup: someFunc3,
  });
  
  Which is the same as
  
  someDivElement.addEventListener("mousedown", someFunc1);
  someDivElement.addEventListener("mousemove", someFunc2);
  someDivElement.addEventListener("mouseup", someFunc3);
  
  @param {Emitter} emitter some object that emits events and has a function `addEventListener`
  @param {Object.<string, function>} listeners eventname function pairs.