Removed NuGet exe & targets

These are no longer required with VS + NuGet v3.

Author: leekelleher

src/.nuget/NuGet.exe

@@ -8,8 +8,6 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".nuget", ".nuget", "{CEE9961C-D747-40CD-B0B2-868D6B46833E}"
 	ProjectSection(SolutionItems) = preProject
 		.nuget\NuGet.Config = .nuget\NuGet.Config
-		.nuget\NuGet.exe = .nuget\NuGet.exe
-		.nuget\NuGet.targets = .nuget\NuGet.targets
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Docs", "Docs", "{D588B45D-9E67-4136-8271-2B8724C8165F}"

src/.nuget/NuGet.targets

@@ -258,13 +258,6 @@
   </ItemGroup>
   <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <Import Project="$(SolutionDir)\.nuget\NuGet.targets" Condition="Exists('$(SolutionDir)\.nuget\NuGet.targets')" />
-  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
-    <PropertyGroup>
-      <ErrorText>This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
-    </PropertyGroup>
-    <Error Condition="!Exists('$(SolutionDir)\.nuget\NuGet.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\.nuget\NuGet.targets'))" />
-  </Target>
   <PropertyGroup>
     <PostBuildEvent>IF %25ComputerName%25 == MBP13-PC-BC (
   IF NOT "$(SolutionDir)" == "*Undefined*" (