Add support for scrolling things other than `window`

[wesleytodd]

Something like this:

scrollTo({
  element: document.querySelector('.some-element'),
  x: 100
});

[cwebley]

Was just thinking about this too. Not extremely familiar with this, but it looks like a slightly different api:

window

// scroll to top left of page
window.scroll(0, 0)

element

// set element scroll position to top left:
ele.scrollLeft = 0;
ele.scrollTop = 0;

we could definitely handle the element case and default to window if element is undefined

[wesleytodd]

hmm, yeah seems like more work than I thought. I still think that the exposed api could be like I said above, but the implementation itself might have to change. I was originally thinking it would just be:

options.element = options.element || window;
// ...
options.element.scroll();

[cwebley]

Yeah that's what I was hoping too. Anyway, I can do this after I finish up some other work this week if you think we'll use element scrolling soon

[wesleytodd]

No rush, but it would be nice to use this in the chat's "scroll to bottom" button

[wesleytodd]

Closed in #7