Don't invalidate previous one-time login URLs

This module always resets the user's password, which has the downside of also invalidating the one-time login URL which most users will use to login to the site. This can cause confusion if the user is searching through their e-mails and tries to connect using an outdated login.

The solution to this problem is to not reset the user's password. This isn't an issue if the admin doesn't bother including the password in the welcome email (most users would probably prefer to just click a link rather than having to retype a temporary password).

The attached patch makes the password reset an optional setting which can be configured by the admin. If you don't bother including the temporary password in the email, it allows previous one-time login URLs to remain valid. If you do include the password, it will simply be listed as "[Hidden]" on reminder emails (the user can still dig up the original email and use that password).