We should store only lowercase usernames and emails

[ctgraham]

In the release for 3.3, we should key on lowercase usernames:

pkp-betterPassword/classes/BadpwFailedLoginsDAO.php

Line 64 in 1a7a297

WHERE username = ?

Core enforces the lowercasing here:
https://github.com/pkp/pkp-lib/blob/edeb7094764d7c289796fef23116a916e80716a2/classes/user/DAO.php#L230

Also for 3.4 with usernames and emails:
https://github.com/pkp/pkp-lib/blob/edeb7094764d7c289796fef23116a916e80716a2/classes/user/DAO.php#L230
https://github.com/pkp/pkp-lib/blob/edeb7094764d7c289796fef23116a916e80716a2/classes/user/DAO.php#L248