Faux 'position: sticky' module 

Needed a simple js 'position sticky' module for a MPU test

Also, often we need access to the non-debounced window events (scroll, etc), so removed it from the mediator events, and moved the onus on the listener to throttle/debounce
So when a debounced func is fired precisely once, it will be delayed by 200ms, because it's asking to execute on trailing edge by default. I think that's the only difference; throttle responds immediately as it's leading edge by default.

https://github.com/lodash/lodash/blob/master/lodash.js#L6409