Modify includes wildcard to allow subdirectories

Author: Lamparter

src/sdk/IronPython.Sdk/Sdk/Sdk.props

@@ -13,7 +13,7 @@
     <RootNamespace>$(Name)</RootNamespace>
   </PropertyGroup>
   <ItemGroup>
-    <Compile Include="*.py" Exclude="obj\**;bin\**"/>
+    <Compile Include="**\*.py" Exclude="obj\**;bin\**"/>
   </ItemGroup>
   <ItemGroup>
     <InterpreterReference Include="Global|IronPython|3.4" />