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/Module.cpp

@@ -0,0 +1,8 @@
+#include "Module.h"
+
+using namespace Leon;
+
+Module::Module()
+{
+
+}