Fixed|GL: Black screen after startup

The OpenGL context was not active sometimes when the UI atlas was
initialized, causing its size to be (0,0). This meant no UI textures
were available for drawing.

IssueID #2246

doomsday/apps/client/src/dd_main.cpp

@@ -1254,7 +1254,8 @@ void DD_FinishInitializationAfterWindowReady()
     try
     {
         initializeWithWindowReady();
-        App::app().notifyStartupComplete();
+        // Let everyone know we're up and running (via another timer callback).
+        Loop::get().timer(0.1, [] () { App::app().notifyStartupComplete(); });
         return;
     }
     catch (Error const &er)

doomsday/apps/client/src/ui/widgets/packageswidget.cpp

@@ -688,6 +688,7 @@ DENG_GUI_PIMPL(PackagesWidget)
             mainCallForIdentify.enqueue([this] ()
             {
                 //qDebug() << "Bundles identified, re-populating" << &self;
+                root().window().glActivate();
                 populateEnabled = true;
                 self().populate();
             });