Inconsistent left or right margins on admin screens

[scribu]

There are a couple of admin screens where the screen icon is not aligned to the left of the content.

dashboard CSS fix

Incomplete patch, and the current patch for the dashboard will need to be confirmed for all browsers. (IE doesn't support adjacent selectors until v8 I think.) Very trivial, we can handle this in a future release.

Adding fix for dashboard page. Left margin inconsistency on settings page is due to padding on the table cell for the label. I think that might be addressed in #16413. Also, the icon may never exactly match up since some of the images are skinnier than the div and have extra space on either side once in a while. Don't know if left-aligning that image would be a good idea though.

This patch also doesn't rely on the adjacent selector, so it works in versions of IE as well.

It's actually worse now, since it doesn't allign with the new header either:

Nevermind that last comment, I was on 3.2.

Notice the misalignment between:

• the user avatar (2px)
• the help tab (-9px)
• the search button (-1px)
• the pagination button (-1px)
• the table

Going through old tickets. What still remains? I only see that the screen meta stuff isn't aligned on either side. Added a patch for that, since I was looking at it already.