Reapply theme coloring

Upstream got rid of theme recoloring, but I thought ours worked pretty
good, so I decided to reapply it. This commit also reapplies commit
ee370f0e13.

Actually, upstream's new dark theme blends pretty well with Breeze Dark
under KDE on Arch Linux. Still, our themes will be reintroduced (and set
as default).

Co-authored-by: akleja <storspov@gmail.com>
Signed-off-by: Avery King <avery98@pm.me>

libraries/image-compiler/imageCompilerMain.cpp

@@ -77,6 +77,9 @@ bool App::OnInit()
    // Leave no persistent side-effect on preferences
    SettingScope scope;
 
+   // Don't blend colors
+   GUIBlendThemes.Write(false);
+
    // So that the program can interpret PNG
    wxInitAllImageHandlers();