Creating usernames with a 't' comes up as an invalid character.

Issue Summary

Creating a new account and using a username with a 't' in the name returns "The username contains an illegal character, like , :." The regular expression test in _htpasswdsync_validate() on line 339 of htpasswdsync.module does not work. Instead of sing "\t", using [[:space:]] works for all whitespace. That makes the check simply [:[[:space:]]]:

Note: I have not tested this extensively but it *seems* to work.