Rename util_show_error_page() to util_show_error_page_and_exit() and redirect() to util_redirect_and_exit()

so it is explicit that we exit in those functions that so we know it isn't necessary to put an exit after
we call them

include/incl.php

@@ -164,16 +164,6 @@ function apidb_image($name)
 }
 
 
-/**
- * redirect to $url
- */
-function redirect($url)
-{
-    header("Location: ".$url); 
-    exit;
-}
-
-
 /**
  * format a date as required for HTTP by RFC 2068 sec 3.3.1 
  */