Databindings - Added conditional databindings

Conditions - Added easy method for null-handling in operators

src/Artemis.UI/Screens/ProfileEditor/Conditions/DataModelConditionGroupViewModel.cs

@@ -142,6 +142,15 @@ namespace Artemis.UI.Screens.ProfileEditor.Conditions
 
             if (IsRootGroup && Parent is DisplayConditionsViewModel displayConditionsViewModel)
                 displayConditionsViewModel.DisplayStartHint = !Items.Any();
+
+            OnUpdated();
+        }
+
+        public event EventHandler Updated;
+
+        protected virtual void OnUpdated()
+        {
+            Updated?.Invoke(this, EventArgs.Empty);
         }
     }
 }

src/Artemis.UI/Screens/ProfileEditor/Conditions/DataModelConditionPredicateViewModel.cs

@@ -157,6 +157,7 @@ namespace Artemis.UI.Screens.ProfileEditor.Conditions
                     RightSideInputViewModel.ValueUpdated += RightSideOnValueEntered;
                 }
 
+                RightSideInputViewModel.Value = DataModelConditionPredicate.RightStaticValue;
                 if (RightSideInputViewModel.TargetType != targetType)
                     RightSideInputViewModel.UpdateTargetType(targetType);
             }