ZKL: some ui tweak

1) minimize white margin around the edge of MainWindow (so DimGrey colour is more) ( https://github.com/xponen/Zero-K-Infrastructure/commit/5cb2fa7336b6c0c352737a77a2978c6c331a448c ) and fit content area with the navigation bar tightly (so it don't appear below Back/Forward button) https://github.com/xponen/Zero-K-Infrastructure/commit/88f867eec33f5e3fb6939d43459330dd9475302d
2) strip out any colour char from system tray pop-up (so it look tiny bit more polished, since it can't colour the text anyway)
3) some more tweak to tooltip, allow tooltip to display for more than 2 ZKL window at once as long as its not overlapping too much (because still not perfect system).

4) fix https://github.com/ZeroK-RTS/Zero-K-Infrastructure/issues/222 &  https://github.com/ZeroK-RTS/Zero-K-Infrastructure/issues/217