Copy resource files into output directory. (#126)

This will make it easier to build locally and run OverlayPlugin out
of the `out/Release` or `out/Debug` directory.

For reference, the xcopy flags are:
* /d only copy newer files
* /e copy all subdirectories
* /i consider destination is a directory even if it doesn't exist
* /q only print a summary line
* /r copy read-only files (just in case)
* /h copy hidden/system files (just in case)
* /y prevent prompts for overwriting destination files

Fixes RainbowMage#52

OverlayPlugin.Core/OverlayPlugin.Core.csproj

@@ -37,6 +37,9 @@
     <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
+  <PropertyGroup>
+    <RunPostBuildEvent>OnBuildSuccess</RunPostBuildEvent>
+  </PropertyGroup>
   <ItemGroup>
     <Reference Include="Advanced Combat Tracker, Version=3.4.9.271, Culture=neutral, PublicKeyToken=a946b61e93d97868, processorArchitecture=x86">
       <SpecificVersion>False</SpecificVersion>
@@ -533,8 +536,7 @@
   <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
-    <PostBuildEvent>
-    </PostBuildEvent>
+      <PostBuildEvent>xcopy /d /e /i /q /r /h /y $(ProjectDir)\resources $(TargetDir)\..\resources</PostBuildEvent>
   </PropertyGroup>
   <!-- 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.
@@ -543,4 +545,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>