Email messaging username field in admin should not be restricted to email format. Closes orchestral/orchestra#176.

Signed-off-by: crynobone <crynobone@gmail.com>
Avoid using static in `Orchestra\Support\Validator`. Closes #32.

Signed-off-by: crynobone <crynobone@gmail.com>
Fix for admin user delete link in the Html UserPresenter.php