spin: fix spin when he is part of button
Merge pull request #415 from bem/#414

Spin in button doesn't look good (fix #414)
use keyboard__codes

closes #408
Merge pull request #417 from bem/issues/408@v2

Use keyboard__codes
popup: border => box-shadow
input: border => box-shadow
button: border => box-shadow
checkbox: border => box-shadow
fix button