New extendable mechanism for disabling units

OpenRa.Mods.RA/OpenRa.Mods.RA.csproj

@@ -53,6 +53,7 @@
     <Compile Include="C4Demolition.cs" />
     <Compile Include="EngineerCapture.cs" />
     <Compile Include="InfiltrateForSonarPulse.cs" />
+    <Compile Include="RequiresPower.cs" />
     <Compile Include="Mine.cs" />
     <Compile Include="MineImmune.cs" />
     <Compile Include="Minelayer.cs" />
@@ -72,6 +73,9 @@
       <Name>OpenRa.Game</Name>
     </ProjectReference>
   </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Orders\" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.