Multiple scroll behavior

[Helveg]

Hi, great package!

I use it to allow the user to scroll to different sections of the FAQ with a sticky floating sidebar. But whenever the user clicks multiple sections in rapid succession the screen starts flickering, probably because the multiple animations force the screen to different positions.

Could you either:

• Provide access to the running animation allowing us to cancel it or to queue up callbacks when this animation finishes (preferably an Observable)
• Provide another optional parameter to the scrollToElement call that allows us to specify whether we want to place this scroll command in the queue to fire after all current scroll commands or to replace all current scrolling commands with the new one?