[MERGE] Add --custom to Version Info in User Guide

[Ian Clatworthy]

Ian Clatworthy has voted tweak.
Status is now: Semi-approved
Comment:
I'm not sure if Windows command line quoting can handle the escaped 
backslashes. You might want to explicitly check that on IRC with someone 
running Windows. If it doesn't work, at we minimum we need to say "on 
Unix" when introducing the example.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C47C1C760.8080105%40wartburg.edu%3E