Change login “Username” label to “Username or Email”

/**
 * The plugin currently allows login using Username OR Email but
 * the field label still reflects just username (that will be
 * changing when translators catch up on translation). In the 
 * meantime, you can change it with a couple of filters added
 * to your theme's functions.php file.
 */
add_filter( 'wpmem_inc_login_inputs', function( $defaults ) {
    $defaults[0]['name'] = "Username or Email";
    return $defaults;
});
add_filter( 'wpmem_sidebar_form', function( $html ) {
    if ( ! strpos( $html, 'Username or Email' ) ) {
        $html = str_replace( 'Username', 'Username or Email', $html );
    }
    return $html;
});