move Building et al into Mods/

OpenRA.Editor/OpenRA.Editor.csproj

@@ -145,6 +145,10 @@
       <Project>{0DFB103F-2962-400F-8C6D-E2C28CCBA633}</Project>
       <Name>OpenRA.Game</Name>
     </ProjectReference>
+    <ProjectReference Include="..\OpenRA.Mods.RA\OpenRA.Mods.RA.csproj">
+      <Project>{4A8A43B5-A9EF-4ED0-99DD-4BAB10A0DB6E}</Project>
+      <Name>OpenRA.Mods.RA</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <Content Include="OpenRA.Editor.Icon.ico" />

OpenRA.Editor/RenderUtils.cs

@@ -8,10 +8,12 @@
  */
 #endregion
 
+using System;
 using System.Drawing;
 using System.Drawing.Imaging;
 using OpenRA.FileFormats;
 using OpenRA.Traits;
+using OpenRA.Mods.RA.Buildings;
 
 namespace OpenRA.Editor
 {