Added instance variable for password and associated getter/setter as
this field is required for the 'add user' gitlab api call
Ugg, white space changers... this checkin looks larger than it is. The
TL;DR is that I've added a 'createUser' function that take a GitlabUser
as an argument and will create the user provided you don't break any of
the API rules. Have pondered adding checkers so at least the 'exception'
is more useful (because the api certainly is not).