Execute SQL tab: Add search bar for SQL code #191

The find operations in QScintilla are used for implementing a find frame
in the SQL Editor of the main window. A checkable tool button is added
in the SQL Editor toolbar for showing and hiding this frame.

There are check boxes for Whole Words, Case Sensitive and Regular
Expressions. The QScintilla facilities in the findFirst method are used
for the implementation.

src/SqlExecutionArea.h

@@ -29,15 +29,22 @@ public:
     SqliteTableModel* getModel() { return model; }
     SqlTextEdit* getEditor();
     ExtendedTableWidget *getTableResult();
-    
+
 public slots:
     virtual void finishExecution(const QString& result);
     virtual void saveAsCsv();
     virtual void saveAsView();
     virtual void reloadSettings();
     void fetchedData();
+    void setFindFrameVisibility(bool show);
+
+private slots:
+    void findPrevious();
+    void findNext();
+    void findLineEdit_textChanged(const QString& text);
 
 private:
+    void find(QString expr, bool forward);
     DBBrowserDB& db;
     SqliteTableModel* model;
     QString sqlFileName;