#97 [patch] Don't override app-specific palette

[John Lindgren]

Currently when a palette is set by qt5ct, it overrides any app-specific palette. It would be nice if qt5ct would only set the platform palette (i.e. QPlatformTheme::SystemPalette) and still allow apps to set/adjust their own palette when desired.

Test case: set "dusk" color scheme via qt5ct configuration, then start Audacious. In Audacious settings window, try to switch from Native to Dark theme. Currently it doesn't work, the palette set by qt5ct overrides the one Audacious tries to set.

Patch to fix the issue attached. This would probably fix issue #54 as well.