Add new to RangeError

Although it is optional, when not including `new` you potentially lose a single useful frame in the stack trace and add a useless frame.

nodejs/node#1246

Closes #32.

punycode.js

@@ -64,7 +64,7 @@
 	 * @returns {Error} Throws a `RangeError` with the applicable error message.
 	 */
 	function error(type) {
-		throw RangeError(errors[type]);
+		throw new RangeError(errors[type]);
 	}
 
 	/**