Add hysteresis

The fact that `nonInteraction` defaults to `true` hints at a deeper issue:

Just one movement of the mouse shouldn't make the user be considered active.

What I'd like is a threshold on a low pass filter on user activity.

Here's a very basic implementation that I'm using, but it probably needs more design before it's fit for public release:

https://gist.github.com/SonOfLilit/421c9f89bfdf6f803198
