new_contents: import sublime
  import sublime_plugin
  import urllib
  
  class GetWebpageSourceCommand(sublime_plugin.TextCommand):
    def run(self, edit):
      url = self.view.substr(self.view.sel()[0])
  
      if len(url) == 0:
        return
  
      output = ""
  
      r = urllib.request.urlopen(url)
  
      output = str(r.read(), encoding='utf8')
  
      newView = sublime.active_window().new_file()
  
      newView.insert(edit, 0, output)
  
subject: Load the source from a highlighted URL into a new window