Display conditions - Added (empty) VMs and test views

src/Artemis.UI/Screens/Module/ProfileEditor/DisplayConditions/Abstract/DisplayConditionViewModel.cs

@@ -0,0 +1,16 @@
+using Stylet;
+
+namespace Artemis.UI.Screens.Module.ProfileEditor.DisplayConditions.Abstract
+{
+    public abstract class DisplayConditionViewModel : PropertyChangedBase
+    {
+        protected DisplayConditionViewModel()
+        {
+            Children = new BindableCollection<DisplayConditionViewModel>();
+        }
+
+        public BindableCollection<DisplayConditionViewModel> Children { get; }
+
+        public abstract void Update();
+    }
+}