类库（包）和NuGet包

Question

我在VS 2015中创建了一个新的类库（Package）项目，并添加了对Microsoft.Owin包的引用，但是我无法访问Microsoft.Owin命名空间。

这是我的project.json文件：

{
  "version": "1.0.0-*",
  "description": "Class1 Class Library",
  "authors": [ "sebastiano.roncato" ],
  "tags": [ "" ],
  "projectUrl": "",
  "licenseUrl": "",

  "dependencies": {
    "System.Collections": "4.0.10-beta-23019",
    "System.Linq": "4.0.0-beta-23019",
    "System.Threading": "4.0.10-beta-23019",
    "System.Runtime": "4.0.10-beta-23019",
    "Microsoft.CSharp": "4.0.0-beta-23019",
    "Microsoft.Owin": "3.0.0",
    "Owin": "1.0.0"
  },

  "frameworks": {
    "dotnet": { }
  }
}