Add AppModel and AppView for loading apps and modify BoxArtManager to return QUrls for QML

app/main.cpp

@@ -2,6 +2,7 @@
 #include <QQmlApplicationEngine>
 
 #include "gui/computermodel.h"
+#include "gui/appmodel.h"
 
 // Don't let SDL hook our main function, since Qt is already
 // doing the same thing
@@ -28,6 +29,7 @@ int main(int argc, char *argv[])
 
     // Register our C++ types for QML
     qmlRegisterType<ComputerModel>("ComputerModel", 1, 0, "ComputerModel");
+    qmlRegisterType<AppModel>("AppModel", 1, 0, "AppModel");
 
     // Load the main.qml file
     QQmlApplicationEngine engine;