Visual design for logout/login/lockscreen

[David Edmundson]

> * I think is just fine using the default theme and swapping textcolors and
> backgroundcolors for the rectangles: to me it looks way better if even if is
> dark, the two buttons still look light/default

Toolbuttons were the big problem with just hardcoding colours for text
and background

 - if the icon is black you can't see it on the background
 - if the icon is also hardcoded to white, you can't see it when you
do the mouseover

 - if you avoid using a toolbutton and load them as images hardcoded
to white, you have no indication that it's a button, and it's bad to
have some buttons behaving differently