Added option to bind light source to scroll position (also removed console logs)

[cmd-kae]

There are inline styles on the body and h1 in the mouse-follow demo to better immediately demonstrate the added option. I also removed the console logs.

[mrtdeh]

Fd

[benjaminbojko]

Thanks for the contribution -- I added your fix to remove the console logs and it's in the latest versions. Regarding the scroll example: I want to keep the demos as simple as possible and all code styles consistent. It might make sense to add another scrolling demo, so if you're up for it perhaps that's a better place for that code. Actual implementation is up to the users of the library -- following the mouse is just one example to understand the concept.