Allow interruption of queued scroll commands - ability jerk back about comfortable-motion.vim HOT 1 OPEN

@bugeats

Give it a flick, and then press your thumb down when see the destination arrive.

Ah, yes, it must be nice.

It can be realized by providing a way to directly set the velocity to 0.
It would be also nice to have a helper function that works like comfortable_motion#flick() but, if a given direction is opposite to the current scrolling, stops the scroll immediately.

Right now what happens is that after all the forward commands finish, the back command then plays out subsequently.

There is no queue in my implementation.
Previously, there was the possibility that two simulation threads run in parallel,
and I think what you saw was caused by the problem.

By the merged PR #23, I believe this queue-like behavior is now fixed.

from comfortable-motion.vim.