fixed http status line

utils.php

 
 function error($code, $message)
 {
-  header("HTTP/ $code $message");
+  http_response_code($code);
+  /* header("HTTP/ $code $message"); */
   die(json_encode(array("code" => intval($code), "message" => $message)));
 }
 
 
 function check_float($f, $def = null)
 {
-  return ($f == (string)(float)$f) ? $f : $def;
+  return is_numeric($f) ? $f : $def;
 }
 
 function check_int($i, $def = null)
 {
-  return is_numeric($i) ? $i : $def;
+  return is_numeric($i) && $i == (int)$i ? $i : $def;
 }
 
 function check_table_field($header, $table, $field)