getChildByName(name) {
		return this.getChildByProp("name", name);
	}
returns the list of childs with the specified name<br>
as defined in Tiled (Name field of the Object Properties)<br>
note : avoid calling this function every frame since
it parses the whole object list each time
@param {string|RegExp|number|boolean} name - child name
@returns {Renderable[]} Array of children