See if we can fix appveyor by forcing redirects.

src/ImageSharp/ImageSharp.csproj

@@ -29,7 +29,7 @@
     <DebugType Condition="$(codecov) == ''">portable</DebugType>
     <DebugSymbols>True</DebugSymbols>
     <Features>IOperation</Features>
-    <LangVersion>7.3</LangVersion>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="..\Shared\*.cs" Exclude="bin\**;obj\**;**\*.xproj;packages\**" />

tests/ImageSharp.Tests/ImageSharp.Tests.csproj

@@ -2,13 +2,14 @@
   <PropertyGroup>
     <TargetFrameworks>net471;netcoreapp2.0;netcoreapp2.1;net47;net462</TargetFrameworks>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
-    <LangVersion>7.2</LangVersion>
+    <LangVersion>latest</LangVersion>
     <DebugType Condition="$(codecov) != ''">full</DebugType>
     <DebugType Condition="$(codecov) == ''">portable</DebugType>
     <DebugSymbols>True</DebugSymbols>
     <RootNamespace>SixLabors.ImageSharp.Tests</RootNamespace>
     <AssemblyName>SixLabors.ImageSharp.Tests</AssemblyName>
     <Platforms>AnyCPU;x64;x86</Platforms>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
@@ -22,9 +23,6 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <WarningsAsErrors />
   </PropertyGroup>
-  <ItemGroup>
-    <None Include="PixelFormats\PixelOperationsTests.Blender.cs" />
-  </ItemGroup>
   
   <ItemGroup>
     <PackageReference Include="Magick.NET-Q16-AnyCPU" Version="7.5.0" />