Add dark and light theme to editor config page.

The dark and light themes are hardwired into Seer.
After applying one of them, you can tweak them.
Then save the configuration.

src/SeerEditorManagerWidget.cpp

@@ -16,10 +16,10 @@
 SeerEditorManagerWidget::SeerEditorManagerWidget (QWidget* parent) : QWidget(parent) {
 
     // Initialize private data
-    _editorFont                = QFont("Source Code Pro", 10);              // Default font.
-    _editorHighlighterSettings = SeerHighlighterSettings::populateForCPP(); // Default syntax highlighting.
+    _editorFont                = QFont("Source Code Pro", 10);                // Default font.
+    _editorHighlighterSettings = SeerHighlighterSettings::populateForCPP(""); // Default syntax highlighting.
     _editorHighlighterEnabled  = true;
-    _editorKeySettings         = SeerKeySettings::populate();               // Defualt key settings.
+    _editorKeySettings         = SeerKeySettings::populate();                 // Defualt key settings.
     _assemblyWidget            = 0;
 
     // Setup UI