Bug/notice errors

When there are no results, the plugin generates the following warnings:

Notice: Undefined variable: emails in /…/wp-content/plugins/bulk-delete-users-by-email/plugin.php on line 84

Warning: array_unique() expects parameter 1 to be array, null given in /…/wp-content/plugins/bulk-delete-users-by-email/plugin.php on line 46

Warning: Invalid argument supplied for foreach() in /…/wp-content/plugins/bulk-delete-users-by-email/plugin.php on line 48