reintroduce Cached<T>; use for Actor.Bounds, Actor.ExtendedBounds, which replace Actor.GetBounds(bool)

OpenRA.FileFormats/OpenRA.FileFormats.csproj

@@ -114,6 +114,7 @@
     <Compile Include="FileFormats\Blast.cs" />
     <Compile Include="Filesystem\ZipFile.cs" />
     <Compile Include="InstallUtils.cs" />
+    <Compile Include="Primitives\Cached.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
@@ -123,4 +124,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>