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/element/QtCodeFile.h

@@ -14,6 +14,7 @@
 
 class QLabel;
 class QPushButton;
+class QtCodeArea;
 class QtCodeFileTitleButton;
 class QtCodeNavigator;
 class QtCodeSnippet;
@@ -59,6 +60,8 @@ public:
 	void updateSnippets();
 	void updateTitleBar();
 
+	void findScreenMatches(const std::string& query, std::vector<std::pair<QtCodeArea*, Id>>* screenMatches);
+
 public slots:
 	void clickedMinimizeButton();
 	void clickedSnippetButton();