オブジェクトを結合する。

extend.js

	/**
	 * Merge defaults with user options
	 * @private
	 * @param {Object} defaults Default settings
	 * @param {Object} options User options
	 * @returns {Object} Merged values of defaults and options
	 */
	var extend = function (defaults, options) {
		var extended = {};
		var prop;
		for (prop in defaults) {
			if (Object.prototype.hasOwnProperty.call(defaults, prop)) {
				extended[prop] = defaults[prop];
			}
		}
		for (prop in options) {
			if (Object.prototype.hasOwnProperty.call(options, prop)) {
				extended[prop] = options[prop];
			}
		}
		return extended;
	};