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

vendorview.php

@@ -20,12 +20,12 @@ $oVendor = new Vendor($aClean['iVendorId']);
 if ($aClean['sSub'])
 {
     if(!$_SESSION['current']->hasPriv("admin"))
-        util_show_error_page("Insufficient privileges.");
+        util_show_error_page_and_exit("Insufficient privileges.");
 
     if($aClean['sSub'] == 'delete')
     {
         $oVendor->delete();
-        redirect($_SERVER['PHP_SELF']);
+        util_redirect_and_exit($_SERVER['PHP_SELF']);
    }
 
 }