Numerous fixes

[phazei]

This totally breaks all the test, if I have time to figure them out, I'll see what I can do.

• Fixes the demo page.
• Refactors the way options are submitted with clear defaults and ability to use a option config object on the directive.
• Fixes handling of offsetBottom when attached top and offsetTop when attached bottom.
• Adds classes attached to object for before it goes sticky, and after it goes sticky
• Adds zIndex option