ui: Added on-screen search feature (issue #79)

* Use menu action "Edit -> Find in View" or Ctrl + D
* UI displayed as search bar at bottom of main window
* Hide search bar with ECS or close button
* Entering a query searches in name of graph nodes and code contents of code view
* Use Enter to iterate through matches, well move match into view in graph and code view
* Checkboxes allow for adding/removing results for certain views
* Create Bookmark shortcut is now CTRL + S

bug id = 79

src/lib_gui/qt/window/QtMainWindow.h

@@ -78,6 +78,10 @@ public:
 
 	void setContentEnabled(bool enabled);
 
+signals:
+	void showScreenSearch();
+	void hideScreenSearch();
+
 protected:
 	void keyPressEvent(QKeyEvent* event);
 	void contextMenuEvent(QContextMenuEvent* event);
@@ -109,6 +113,7 @@ public slots:
 
 	void find();
 	void findFulltext();
+	void findInView();
 	void codeReferencePrevious();
 	void codeReferenceNext();
 	void overview();