Fixed CSS-warnings

This patch fetches the following CSS-properties and give appropriate warnings:
_width, min-width, max-width,_
_height, min-height, max-height,_
_padding, padding-bottom, padding-left, padding-right, padding-top,_
_margin, margin-bottom, margin-left, margin-right, margin-top,_
_position_

Question:
Are there any other properties which makes troubles or are these properties still problematic in modern viewers? ...mail-clients evolved over time.