Copying the contentFiles to output so tests can access them

By copying these files to the output, referecing projects such
as the test projects, will automatically get a copy of these
files in their output, which makes it possible to reference
them for the unit tests that create in-memory projects that
need to use these APIs as if the package was installed.

src/Moq/Moq/Moq.csproj

@@ -13,7 +13,7 @@
   <ItemGroup>
     <Compile Remove="contentFiles\**\*.cs" />
     <None Remove="contentFiles\**\*.*" />
-    <None Include="contentFiles\**\*.*" Pack="true" />
+    <None Include="contentFiles\**\*.*" Pack="true" CopyToOutputDirectory="PreserveNewest" />
   </ItemGroup>
 
   <ItemGroup>

src/Stunts/Stunts/Stunts.csproj

@@ -11,7 +11,7 @@
   <ItemGroup>
     <Compile Remove="contentFiles\**\*.cs" />
     <None Remove="contentFiles\**\*.*" />
-    <None Include="contentFiles\**\*.*" Pack="true" />
+    <None Include="contentFiles\**\*.*" Pack="true" CopyToOutputDirectory="PreserveNewest" />
   </ItemGroup>
 
   <ItemGroup>