Affix and Spyscroll

I am missing the tests, but the demo and src should work otherwise.  I will work on the tests tomorrow, but could probably use some help, since I'm new to writing them.

If anything isn't clear in my code, please let me know and I'd be happy to expand on it.

Affix works (functionally) identically to the bootstrap original version.  Scrollspy is very similar but I implement it in a slightly different (I think, better/more angular) way.

I am missing:  tests and scrollspy highlighting of the dropdown.

Matt