Add options to define window title foreground and background in the group settings

[gensenio]

I would like to have an option to define customized window title foreground color and background color (and maybe outline color) in the group options

This for easily recognize some apps from others.

[joewing]

This shouldn’t be too hard to support. There is a similar request for trays (issue #39).

[gensenio]

ok, thanks for considering it!

[inkeso]

I second this. But because I'm inpatient and don't mind hardcoding stuff, i did this: I wanted different colors for apps from different machines (ssh -Y user@box app) and i don't use Tray or TaskList so i misused its Background. It is a filthy hack but i wanted to share it nonetheless. machinecolor.patch.txt

I will try to fix this issue correctly but it may take a while. So what about the Options-Format?

    <Group>
        <Option>foreground:#FFFFFF</Option>
        <Option>background:#017383:#07363C</Option>
        <Option>outline:#017383</Option>
    </Group>

What should happen if a window is in several groups with a different colors? Where is a good place to apply the color, border.c:DrawBorderHelper?

PS. Selecting groups by WM_CLIENT_MACHINE may be a good idea too.