-Added support for immutable collections to Portable .NET 4.0 build

Src/Newtonsoft.Json/Newtonsoft.Json.Portable40.csproj

@@ -224,6 +224,7 @@
     <Compile Include="Utilities\ExpressionReflectionDelegateFactory.cs" />
     <Compile Include="Utilities\FSharpUtils.cs" />
     <Compile Include="Utilities\ILGeneratorExtensions.cs" />
+    <Compile Include="Utilities\ImmutableCollectionsUtils.cs" />
     <Compile Include="Utilities\JavaScriptUtils.cs" />
     <Compile Include="Utilities\JsonTokenUtils.cs" />
     <Compile Include="Utilities\LateBoundReflectionDelegateFactory.cs" />

Src/Newtonsoft.Json/Serialization/JsonArrayContract.cs

@@ -212,7 +212,7 @@ namespace Newtonsoft.Json.Serialization
             }
 #endif
 
-#if !(NET20 || NET35 || NET40 || PORTABLE40)
+#if !(NET20 || NET35 || NET40)
             Type immutableCreatedType;
             ObjectConstructor<object> immutableParameterizedCreator;
             if (ImmutableCollectionsUtils.TryBuildImmutableForArrayContract(underlyingType, CollectionItemType, out immutableCreatedType, out immutableParameterizedCreator))

Src/Newtonsoft.Json/Serialization/JsonDictionaryContract.cs

@@ -176,7 +176,7 @@ namespace Newtonsoft.Json.Serialization
             }
 #endif
 
-#if !(NET20 || NET35 || NET40 || PORTABLE40)
+#if !(NET20 || NET35 || NET40)
             Type immutableCreatedType;
             ObjectConstructor<object> immutableParameterizedCreator;
             if (ImmutableCollectionsUtils.TryBuildImmutableForDictionaryContract(underlyingType, DictionaryKeyType, DictionaryValueType, out immutableCreatedType, out immutableParameterizedCreator))

Src/Newtonsoft.Json/Utilities/ImmutableCollectionsUtils.cs

@@ -23,7 +23,7 @@
 // OTHER DEALINGS IN THE SOFTWARE.
 #endregion
 
-#if !(NET20 || NET35 || NET40 || PORTABLE40)
+#if !(NET20 || NET35 || NET40)
 using System;
 using System.Collections.Generic;
 using System.Linq;