Benjaminsen/extend.js — pull request #2 by sQu1rr (2014-04-08 10:39:06+00:00)
Title: got rid of argument.callee using NFE, use strict

We can either use NFE, or var ext = Class.extend. Either of them makes sense.
All tests are good, i was worried though for a moment that it implicitly breaks something, but it seems not to.
Also, exporting to globals was broken in strict mode.