Fixed an issue with nlog building on 4.0

Author: niemyjski

Source/Platforms/NLog/Exceptionless.NLog.csproj

@@ -9,7 +9,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>Exceptionless.NLog</RootNamespace>
     <AssemblyName>Exceptionless.NLog</AssemblyName>
-    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <TargetFrameworkProfile>
     </TargetFrameworkProfile>
@@ -41,8 +41,9 @@
     <Prefer32Bit>false</Prefer32Bit>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="NLog">
-      <HintPath>..\..\..\packages\NLog.3.2.1\lib\net45\NLog.dll</HintPath>
+    <Reference Include="NLog, Version=3.2.1.0, Culture=neutral, PublicKeyToken=5120e14c03d0593c, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\..\..\packages\NLog.3.2.1\lib\net40\NLog.dll</HintPath>
     </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />