Close #3001 Improve user add from admin

Set autocomplete off in form tag
http://stackoverflow.com/questions/12374442/chrome-browser-ignoring-autocomplete-off

Make newly created user join default channels

Improvements to create user via admin.
 Option to send welcome email with login details and password
 Buttons to generate random password
 Make password change on login default to YES

Change enrollment to welcome
Enable checkboxes after save or cancel

Set e-mail verified/not verified