Latency/ghosting when scrolling

[syl20bnr]

There is latency when keeping j or k pressed and the buffer continues to scroll when the user stop pressing the keys.

More info in this issue: syl20bnr/spacemacs#6094

[xcodebuild]

I can't reproduce this problem in fact. But I fix another bug with keep j
pressing. Could you try latest version on git?

[syl20bnr]

I tried the last version and it is still here.
Here is another repro step:

• Open doc/DOCUMENTATION.org of Spacemacs
• Expand all and go to the end of file
• keep k pressed a while then press j. On both of my machines (GNU Emacs on OS X and Ubuntu) the point will continue to go up for a random time (sometime during 2 seconds depending on how long I pressed k) and then go down.

[syl20bnr]

This is due to the utilization of an idle timer. I tried without it and plug the refresh function directly in post-command hook and it does not work with smooth-scrolling.

[syl20bnr]

Also I proposed some alternatives on the Spacemacs issue. Absolute lines with nlinum don't suffer ghosting so maybe we could just display relative line when evil is waiting for a motion.