window controls should share a uniform color

[frizzle21]

Binary package hint: compiz

at the moment, window controls are not consistent, since the close/hide button is red, while minimize and maximize are both grey.
This leads to many misunderstandings about what window controls are and why there is a close button on nearly every window, or what the close button is there for.

the only use case i can imagine for coloring the window close button red would be to indicate, whether the close operation will also quit the process or service hosted in that window.