* Configuration object
User's should be able to configure the followingL:
- style object (for the list item... font, colors, etc)
- bool: ignore blank headers (ie, headers with no id's),
- array: list of headers to query from (ie, just h1's... or h2's etc)
- additional padding to scroll when moving down
* Make NPM installable
* DONE Prevent glitchy-ness on mouse enter when mouse-exit functionality is happening.
- throttle
- or have a flag for "active" and prevent mouse-enter things from happening if
  ~active~ is engaged.
- is still a little hacky, but works
* DONE Move styles.css into injectable js
