Fix handling of FormValidator::Simple->check() result * has_error() misses invalid day (eg 1-) which returns has_invalid()- test for result->success instead
adaptations for request form access by non-logged-in user * generate 'centre' token in login() for use in request-form url * adapt create_form_tokens() to accept 'centre' only * Local::Utils encrypt & decrypt functions capture Crypt::CBC errors & return empty not stacktrace
