Simplifying extend/inherits (includes spec)

I've simplified the "extends" / "inherits" behavior here. All the tests still passed, so I presume I retained the desired functionality. (if not, let's add more tests to make sure)

This is meant to also address issue #46, and a test has been added to ensure that I've met that criteria. (it's pretty much the same code I used for the JSFiddle)

Let me know if this is helpful, I'm more than willing to make changes provided we include more tests to cover that.