New strings

en.php

 <?php
 $LANG['auth']['signup'] = 'Sign up';
+$LANG['auth']['login'] = 'Log in';
+$LANG['page']['credits'] = 'Credits';
+$LANG['footer']['executionTime'] = 'Execution time';
 $LANG['generic']['generic'] = 'You\'ve unlocked the generic text!';
 $LANG['generic']['error'] = 'An error occurred.';
 $LANG['error']['generic'] = 'No error message provided.';