HttpClient with Web Api Install-package

Install-Package Microsoft.Net.Http
Install-Package Microsoft.Net.Http -Pre

а лучше загрузить через NuGet

Microsoft Http Clients Libraries
Microsoft Asp.Net Web Api Client Libraries
JSON.Net

Result

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="EntityFramework" version="5.0.0" targetFramework="net45" />
  <package id="Microsoft.AspNet.WebApi.Client" version="4.0.30506.0" targetFramework="net45" />
  <package id="Microsoft.Net.Http" version="2.0.20710.0" targetFramework="net45" />
  <package id="Newtonsoft.Json" version="4.5.11" targetFramework="net45" />
</packages>

then may be useful

Install-Package jquery-globalize