Add more compiler warnings

src/screenoverlay/screenoverlaysettings.cpp

@@ -5,7 +5,7 @@
 #include <QColorDialog>
 
 ScreenOverlaySettings::ScreenOverlaySettings(ScreenOverlay *overlay, QWidget *parent)
-: overlay(overlay), QDialog(parent), ui(new Ui::ScreenOverlaySettings) {
+: QDialog(parent), ui(new Ui::ScreenOverlaySettings), overlay(overlay) {
     ui->setupUi(this);
 
     ui->gridBox->setChecked(overlay->grid());

src/src.pro

@@ -11,6 +11,8 @@ TEMPLATE = app
 
 CONFIG += c++11 thread
 
+QMAKE_CXXFLAGS += -Werror -Wall -Wpedantic -Wextra
+
 # The following define makes your compiler emit warnings if you use
 # any feature of Qt which as been marked as deprecated (the exact warnings
 # depend on your compiler). Please consult the documentation of the