Split into smaller projects, now uses plugins.

RainmeterStudio.Core/Documents/DocumentEditorFeatures/IToolboxProvider.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace RainmeterStudio.Core.Documents.DocumentEditorFeatures
+{
+    public interface IToolboxProvider
+    {
+        bool SupportsToolboxDrop { get; }
+        IEnumerable<string> ToolboxItems { get; }
+
+        event EventHandler ToolboxItemsChanged;
+    }
+}