Improve cmake and GUI (#13)

+ Packaging and CI for Windows, Mac, Linux
+ Debian package, NSIS Windows installer, OSX appbundle
+ Example application using libqtk
+ Component installation for `qtk`, `libqtk`, or `collection` with cmake

src/app/qtkmainwindow.h

@@ -0,0 +1,92 @@
+/*##############################################################################
+## Author: Shaun Reed                                                         ##
+## Legal: All Content (c) 2023 Shaun Reed, all rights reserved                ##
+## About: MainWindow for Qtk application                                      ##
+##                                                                            ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0   ##
+##############################################################################*/
+
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <unordered_map>
+
+#include <QMainWindow>
+#include <QPlainTextEdit>
+
+#include "debugconsole.h"
+#include "qtkwidget.h"
+
+namespace Ui {
+  class MainWindow;
+}
+
+/**
+ * MainWindow class to provide an example of using a QtkWidget within a Qt
+ * window application.
+ */
+class MainWindow : public QMainWindow {
+    Q_OBJECT
+
+  public:
+    /***************************************************************************
+     * Contructors / Destructors
+     **************************************************************************/
+
+    /**
+     * This ctor also initializes the Scene for each QtkWidget in the window.
+     * To load a different scene this would need to be updated.
+     *
+     * @param parent The parent for this QMainWindow
+     */
+    explicit MainWindow(QWidget * parent = nullptr);
+
+    ~MainWindow() override;
+
+    /***************************************************************************
+     * Public Methods
+     **************************************************************************/
+
+    /**
+     * Allows widgets to retrieve an instance of this root QMainWindow.
+     * @return this
+     */
+    static MainWindow * getMainWindow();
+
+    Qtk::QtkWidget * getQtkWidget(int64_t index = 0);
+
+    /**
+     * Accessor for retrieving a QtkWidget by it's objectName.
+     * This function will not construct a new QtkWidget if none is found.
+     *
+     * @param name The objectName associated with the QtkWidget.
+     * @return Pointer to an active QtkWidget or Q_NULLPTR is not found.
+     */
+    Qtk::QtkWidget * getQtkWidget(const QString & name);
+
+  public slots:
+    /**
+     * Trigger a refresh for widgets related to a scene that has been updated.
+     * @param sceneName The name of the scene that has been modified.
+     */
+    void refreshScene(QString sceneName);
+
+  private:
+    /***************************************************************************
+     * Private Members
+     **************************************************************************/
+
+    /** Do not allow copying */
+    MainWindow(const MainWindow &) {};
+
+    Ui::MainWindow * ui_ {};
+    static MainWindow * mainWindow_;
+
+    /**
+     * Maps a scene name to the QtkWidget viewing it.
+     * TODO: Value should be a vector of QtkWidget * for multiple scene views.
+     */
+    std::unordered_map<QString, Qtk::QtkWidget *> views_ {};
+};
+
+#endif  // MAINWINDOW_H