Separated bar background into it's own Xresource.

[jakem72360]

Added the ability to set text color in the bar separately using it's own Xresource. This is because some background/foreground combinations do not provide enough contrast for text-readability.

[jakem72360]

Changed the new option to change the bar background, as the highlights/marks were still unreadable. Apologies for a misleading PR :/

[N-R-K]

Seems like pull requests aren't being accepted anymore. But should be worth pointing out that

bbg = win_res(db, RES_CLASS ".barBackground", "white");

this will break experience for existing users. Better to use fg as a fallback instead of "white" so it stays consistent with previous behavior. It also makes more sense to add barForegound as well.

This is currently what I have on my build: https://dpaste.com/736HJ6J6K