In general, we always use relative URLs (using `_path`), but sometimes
we were accidentally using absolute URLs (using `_url`). It's been
reported i might cause some isuses if accepting both HTTP and HTTPS
connections, although we've never seen the case.
In any case, this change makes the code more consistent and makes the
generated HTML cleaner.
The back button when the user changes the password
(in the print password page) redirects to the
edit manually page.
The routes to access password edit pages has been added,
along with the ones to send reset password email and
reset password manually.
allows managers to create users without email
hides email preferences from account page for email-less users
prevents email delivery to users with no email
adds spec for user creation from management
adds specs for user's email requirement
adds spec for no deliveries if no email
