added gaming core lib

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "gaming-core"]
+	path = gaming-core
+	url = git@git.hammerle.me:kjhammerle/gaming-core.git

Game.cpp

@@ -79,5 +79,5 @@ void Game::render(float lag, Renderer& renderer) const {
 }
 
 bool Game::isRunning() const {
-    return true;//!controller.isDown(Controller::SELECT);
+    return !controller.isDown(Controller::SELECT);
 }

gaming-core

@@ -0,0 +1 @@
+Subproject commit 2520bce011ef46b775b701f024259929351dfd6d