Allow a themable KMess interface and make a WLM2009-ish theme

[sjors]

Somebody wrote in a LikeBack comment: 1) Skinnable Interface. Qt4 supports svg so the ability to use svg-powered styles to completly alter the interface would be awesome!

If this is possible, we should definitely look into it and create a skinnable/themable interface, and probably some kind of a WLM2009 theme for our users coming from WLM2009!