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/treeview.cpp

@@ -0,0 +1,63 @@
+/*##############################################################################
+## Author: Shaun Reed                                                         ##
+## Legal: All Content (c) 2023 Shaun Reed, all rights reserved                ##
+## About: TreeView plugin for scene hierarchy                                 ##
+##                                                                            ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0   ##
+################################################################################
+*/
+
+#include "treeview.h"
+#include "qtkmainwindow.h"
+#include "ui_treeview.h"
+
+/*******************************************************************************
+ * Constructors, Destructors
+ ******************************************************************************/
+
+Qtk::TreeView::TreeView(QWidget * parent) :
+    QDockWidget(parent), ui(new Ui::TreeView) {
+  ui->setupUi(this);
+  connect(
+      ui->treeWidget, &QTreeWidget::itemDoubleClicked, this,
+      &TreeView::itemFocus);
+}
+
+Qtk::TreeView::~TreeView() {
+  delete ui;
+}
+
+/*******************************************************************************
+ * Public Methods
+ ******************************************************************************/
+
+void Qtk::TreeView::updateView(const Qtk::Scene * scene) {
+  ui->treeWidget->clear();
+  ui->treeWidget->setColumnCount(1);
+  mSceneName = scene->getSceneName();
+  auto objects = scene->getObjects();
+  for(const auto & object : objects) {
+    auto item =
+        new QTreeWidgetItem(QStringList(QString(object->getName().c_str())));
+    ui->treeWidget->insertTopLevelItem(0, item);
+  }
+}
+
+void Qtk::TreeView::itemFocus(QTreeWidgetItem * item, int column) {
+  QString name = item->text(column);
+  auto scene = MainWindow::getMainWindow()->getQtkWidget()->getScene();
+  auto & transform = scene->getCamera().getTransform();
+  auto object = scene->getObject(name);
+  if(object == Q_NULLPTR) {
+    qDebug() << "Attempt to get non-existing object with name '" << name
+             << "'\n";
+  }
+  Transform3D * objectTransform;
+  if(object->getType() == Object::QTK_MESH) {
+    objectTransform = &dynamic_cast<MeshRenderer *>(object)->getTransform();
+  } else if(object->getType() == Object::QTK_MODEL) {
+    objectTransform = &dynamic_cast<Model *>(object)->getTransform();
+  }
+  transform.setTranslation(objectTransform->getTranslation());
+  transform.translate(0.0f, 0.0f, 3.0f);
+}