Profile editor - Fixed new elements not rendering while paused

Profile editor - Use default brush on new layers
Profile tree - Implement drag & drop

src/Artemis.Core/Services/Registration/Interfaces/ILayerBrushService.cs

@@ -27,5 +27,7 @@ namespace Artemis.Core.Services
         /// Returns the descriptor of the default layer brush
         /// </summary>
         LayerBrushDescriptor? GetDefaultLayerBrush();
+
+        void ApplyDefaultBrush(Layer layer);
     }
 }

src/Artemis.Core/Services/Registration/LayerBrushService.cs

@@ -46,5 +46,13 @@ namespace Artemis.Core.Services
             defaultReference.Value.BrushType ??= "SolidBrush";
             return LayerBrushStore.Get(defaultReference.Value.LayerBrushProviderId, defaultReference.Value.BrushType)?.LayerBrushDescriptor;
         }
+
+        /// <inheritdoc />
+        public void ApplyDefaultBrush(Layer layer)
+        {
+            LayerBrushDescriptor? brush = GetDefaultLayerBrush();
+            if (brush != null)
+                layer.ChangeLayerBrush(brush.CreateInstance(layer, null));
+        }
     }
 }