title: add files to xcodeproj from command line
body: <p>I need add header and library into project file from command line. (need change project file)</p>
  
  <p>I've looked <strong>project.pbxproj</strong> it looks not friendly :)</p>
  
  <p>Is exist way to add files to xcodeproj correctly ?
  Of course it will be running only in MACOS.</p>
  
  <p>Thanks,</p>