[Spread] Gui: remove unused includes

- also sort includes

src/Mod/Spreadsheet/Gui/LineEdit.cpp

@@ -21,15 +21,16 @@
  ***************************************************************************/
 
 #include "PreCompiled.h"
+
 #ifndef _PreComp_
+# include <QApplication>
 # include <QEvent>
 # include <QKeyEvent>
 #endif
 
-#include <QCoreApplication>
-
 #include "LineEdit.h"
 
+
 using namespace SpreadsheetGui;
 
 LineEdit::LineEdit(QWidget *parent)