Convert a project.json to a csproj without using Visual Studio
<p>As of preview3 <code>dotnet new</code> produces a csproj, and both <code>dotnet restore</code> and <code>dotnet build</code> fail against a project.json and/or an xproj.</p>

<p>For instance, running <code>dotnet restore</code> against a directory that has both a project.json and an xproj gives this error.</p>

<blockquote>
  <p>...xproj(7,3): error MSB4019: The imported project "C:\Program Files\dotnet\sdk\1.0.0-preview3-004056\Extensions\Microsoft\VisualStudio\v14.0\DotNet\Microsoft.DotNet.Props" was not found. Confirm that the path in the  declaration is correct, and that the file exists on disk.</p>
</blockquote>

<p>Further, running it against a directory that has only a project.json gives this error. </p>

<blockquote>
  <p>MSBUILD : error MSB1003: Specify a project or solution file. The current working directory does not contain a project or solution file.</p>
</blockquote>

<p>Without using Visual Studio, how can we convert an existing project.json and/or xproj to a csproj?</p>