title: Adding solution-level items in a NuGet package
body: <p>I want to add solution folders and solution items (not projects) to a solution file via a NuGet package.  I imagine this would be accomplished through Powershell.  I've looked through the documentation for NuGet, Powershell, and EnvDTE and can't figure out:</p>
  
  <ol>
  <li>Which commands/methods I would use?</li>
  <li>Which standard script I would do this in, Init.ps1, Install.ps1, or somewhere else?</li>
  </ol>