Window Title Colour Should Adapt To Background

[modelmat]

... or alternatively, just be configurable, if that's easier

Prior to 0.9.0, on 0.8.0, the title was white. This worked with my dark background:

Now, on 0.9.0, the title is now grey (default colour?). This does not work with my dark background:

[tcorreabr]

In version 0.8 the color of the titles was always white. In version 0.9 the color depends on the Plasma theme you are using.

As I'm using a dark theme I didn't see this coming. In the next version it should be always white again.

[modelmat]

I'm not sure setting the default as white is a good idea - what if you have a white background, the white looks bad?