Reorder includes (local to system)

Include local include first so that dependencies on external includes are less likely overlooked

osciwidget.cpp

@@ -1,14 +1,14 @@
 #include "osciwidget.h"
 
-// system includes
-#include <cmath>
-
 // Qt includes
 #include <QLineF>
 #include <QDebug>
 #include <QPainter>
 #include <QTimerEvent>
 
+// system includes
+#include <cmath>
+
 OsciWidget::OsciWidget(QWidget *parent) :
     QOpenGLWidget{parent},
     m_redrawTimerId(startTimer(1000/m_fps))