Blocking of several users ends prematurely if t comes across a nonexistent/suspended user

[44b7d5d32fc78037566e3b7e07ef10d9]

When blocking multiple users at once (e.g. cat-ing a list and using xargs), t will fail to block any users listed after a nonexistent or suspended user.

For example:
t block User1 NonexistentUser User2

In this case, t will block User1 but will return a Sorry, that page does not exist error for NonexistentUser and exit. User2 will not be blocked.

It would be good if t handled this issue gracefully, preferably with a user friendly message (e.g. "Skipping user .")