Use the new setColors() function.

No intended change.
Make setColors() update all colors.

The constructor no longer needs to do as much, instead, call setColors().
Whitespace changes.

No intended change.
Qt::white isn't the default for mFgColor.

Qt::lightGrey is the default for mFgColor, instead.
Reset all the colors instead of just some.
Use better defaults.

The current defaults are not the standard colors, use standard ones instead.