Added a gutter and currentline highlighting to the SQL editor.

Currently gutter only shows linenumbers. Code is mostly from http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html

There is a little bit included in this commit from a first try to make toobars adept to the current tab.

Code #2

pglab/EditorGutter.h

@@ -0,0 +1,28 @@
+#ifndef EDITORGUTTER_H
+#define EDITORGUTTER_H
+
+#include <QWidget>
+//#include <QPlainTextEdit>
+
+class CodeEditor;
+
+class EditorGutter : public QWidget
+{
+	Q_OBJECT
+public:
+	explicit EditorGutter(CodeEditor *editor);
+
+	QSize sizeHint() const override;
+
+protected:
+
+	void paintEvent(QPaintEvent *event) override;
+
+private:
+	CodeEditor *codeEditor;
+signals:
+
+public slots:
+};
+
+#endif // EDITORGUTTER_H