Dark mode support

Centralized all colors, tweaked application paletter in darkmode to make it darker.

pglab/codeeditor/CodeEditor.h

@@ -3,6 +3,7 @@
 
 #include <QPlainTextEdit>
 #include <set>
+#include "util/Colors.h"
 
 /** This class adds some capabilities to QPlainTextEdit that are useful
  * in code editor scenarios.
@@ -39,6 +40,7 @@ private:
 
 	QTextEdit::ExtraSelection currentLine;
 	QList<QTextEdit::ExtraSelection> errorMarkers;
+    const ColorTheme &colorTheme;
 
 	std::set<int> errorLines;