Allow admins to autogenerate passwords

This is my first attempt at serious drupal hacking.
I tried it on drupal 5.7, I can possibly port this to drupal6, but I probably need a bit of help with code guidelines.

What this patch does is extend the password validator in form.inc to add a checkbox (autogenerate password) that will generate the password. It works, but there are a few details unclear to me.

• I'm unsure how to pass options to a password confirm. So far, I simply set #autogen if I wanted an autogen checkbox.
• I had to move the user_password() function code in there, because I'm uncertain I can use a user.module function from an include file. I left a stub that calls the new function in the user.module. I don't know about naming conventions.
• I haven't figured out how to recover more than a simple value from the password confirm (like, whether the password was autogenerated or not), so I just add the new password value to the message presented to the admin if email confirmation is not set.
• There's a new untranslated string.
• I don't know how to do this with external modules and hooks, which is why I present this as a patch to core.

I am definitely going to use this on a site (where I have an assistant who has to create about 100 accounts each year, where users do not create their own accounts, and where just simplifying this makes sense...)