Layers - Seperated activation and removal of layers/effects

Effects - Added effects UI, order is still a bit messed up and reordering is missed
Effects - Added renaming of effects on the layer

src/Artemis.Core/Plugins/Abstract/LayerBrushProvider.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Artemis.Core.Plugins.Exceptions;
 using Artemis.Core.Plugins.LayerBrush;
@@ -17,6 +18,7 @@ namespace Artemis.Core.Plugins.Abstract
         protected LayerBrushProvider()
         {
             _layerBrushDescriptors = new List<LayerBrushDescriptor>();
+            PluginDisabled += OnPluginDisabled;
         }
 
         /// <summary>
@@ -42,5 +44,10 @@ namespace Artemis.Core.Plugins.Abstract
 
             _layerBrushDescriptors.Add(new LayerBrushDescriptor(displayName, description, icon, typeof(T), this));
         }
+
+        private void OnPluginDisabled(object sender, EventArgs e)
+        {
+            _layerBrushDescriptors.Clear();
+        }
     }
 }