src/javascript/core/EventTarget.js
function(type, fn, priority, scope) {
			var self = this;
			self.bind.call(this, type, function cb() {
				self.unbind(type, cb);
				return fn.apply(this, arguments);
			}, priority, scope);
		}
function(type, fn, priority, scope) {
			var self = this;
			self.bind.call(this, type, function cb() {
				self.unbind(type, cb);
				return fn.apply(this, arguments);
			}, priority, scope);
		}
Register a handler to the event type that will run only once

@method bindOnce
@since >1.4.1
@param {String} type Type or basically a name of the event to subscribe to
@param {Function} fn Callback function that will be called when event happens
@param {Number} [priority=0] Priority of the event handler - handlers with higher priorities will be called first
@param {Object} [scope=this] A scope to invoke event handler in