Greatly improve responsiveness of the virtual keyboard on the website

[vitormv]

Hi, I added some small changes to the CSS of the virtual keyboard, because:

• The current keyboard only fully changes the color to blue if the user presses the key long enough.
• Very quick key presses barely show on the keyboard. Also same happens if you are typing a sentence and normal typing speed, the keyboard barely lits up.
• Currently the keyboard color fades very quickly, if user types while looking at his own keyboard, by the time he/she looks up the screen, color already changed again.

So, since the keyboard is above the fold on the website and therefore the first thing users will play around with, I improved its responsivess by:

• Make the color transition when the key is lighing up extremly fast 1ms, so even extremely quick key presses will be lit up. Try for yourself!
• Slightly increase the fade-out transition, and add a easing method.

[coveralls]

Pull Request Test Coverage Report for Build 210

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 81.364%

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Totals
Change from base Build 208:	0.0%
Covered Lines:	193
Relevant Lines:	207

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💛 - Coveralls

[codecov-io]

Codecov Report

Merging #123 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #123   +/-   ##
=======================================
  Coverage   93.23%   93.23%           
=======================================
  Files           1        1           
  Lines         207      207           
=======================================
  Hits          193      193           
  Misses         14       14

Impacted Files	Coverage Δ
dist/hotkeys.js	93.23% <ø> (ø)	⬆️

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[jaywcjlove]

@vitormv nice! 👍

thx!