Menu icons are off by 1px

[lessbloat]

Props to Nacin for catching this. The menu icons are all down 1px from 3.4, and look off.

22527.diff should do the trick. I also centralized this code in wp-admin.css. There is no need (that I can think of) to have this code in the color's css.

It's worth doing this in two separate patches/commits, otherwise it's impossible to tell what changed.

I'd like to just fix the pixels now, and centralize in 3.6.

Needs testing in these modes, too: manual collapse, auto-fold collapse, and HiDPI.

22527.2.diff​ moves the source back to the color files, but keeps the background-position settings in wp-admin.css

22527.3.diff just fixes the icon positioning (in both color files).

In 22767:

Move the admin menu icons up one pixel, to restore their 3.4 positioning. props lessbloat. fixes #22527.

22527.4.diff:​

• reverts 22767
• Adjusts icon alignment in sprites instead
• Fixes "generic" icon alignment to match the rest
• Fixes HiDPI generic icon alignment so that it doesn't jump 1px on hover

In 22785:

Revert [22767] and fix icon alignment issues in the sprites themselves. props lessbloat. fixes #22527.