title: Vim helptag generation
body: <p>I use pathogen and have an update script that downloads the latest versions of all the vim plugins I use from vim.org, github, or wherever else they may be. However, this script does not currently update the vim helptags. In order to do so, I have to go to each updated plugin in vim and execute ":helptags doc/". It would be great if I could do so with my update script, but in order to do so I need to run the vim ":helptags" command from a script. Is this possible?</p>
  
  <p>Thanks!</p>