Delay showing the Add Machine dialog until after the main window is properly shown

Showing the main window causes the Add Machine window to hide apparently
so instead make sure we show the add machine dialog after showing the
main window.

This also handles the "there is no machine" situation a little more
cleanly.

cura/CuraApplication.py

@@ -173,11 +173,6 @@ class CuraApplication(QtApplication):
         self.setMainQml(Resources.getPath(self.ResourceTypes.QmlFiles, "Cura.qml"))
         self.initializeEngine()
 
-        manager = self.getMachineManager()
-        if not self.getMachineManager().getMachineInstances():
-            self.requestAddPrinter.emit()
-
-
         if self._engine.rootObjects:
             self.closeSplash()
 

resources/qml/Cura.qml

@@ -652,14 +652,30 @@ UM.MainWindow
         onRequestAddPrinter:
         {
             addMachineWizard.visible = true
-            addMachineWizard.firstRun = true
+            addMachineWizard.firstRun = false
         }
     }
 
     Component.onCompleted:
     {
         UM.Theme.load(UM.Resources.getPath(UM.Resources.Themes, "cura"))
-        base.visible = true;
+        visible = true;
+        addMachineTimer.start();
+    }
+
+    Timer
+    {
+        id: addMachineTimer;
+        interval: 100;
+        repeat: false;
+        onTriggered:
+        {
+            if(UM.MachineManager.activeMachineInstance == "")
+            {
+                addMachineWizard.firstRun = true;
+                addMachineWizard.open();
+            }
+        }
     }
 }