Description:
------------
If you create a GdkEvent with the GdkEventType Gdk::KEY_PRESS and try to assign a value to the keyval field the keyval field does not change.

Test script:
---------------
$event = new GdkEvent(Gdk::KEY_PRESS);
$event->keyval	= Gdk::KEY_Return;
var_dump($event);

Expected result:
----------------
object(GdkEvent)#4466 (9) {
  ["keyval"]=>
  int(65293)
  ["time"]=>
  int(0)
  ["state"]=>
  int(0)
  ["string"]=>
  string(0) ""
  ["hardware_keycode"]=>
  int(0)
  ["group"]=>
  int(0)
  ["type"]=>
  int(8)
  ["window"]=>
  NULL
  ["send_event"]=>
  bool(false)
}


Actual result:
--------------
object(GdkEvent)#4466 (9) {
  ["keyval"]=>
  int(0)
  ["time"]=>
  int(0)
  ["state"]=>
  int(0)
  ["string"]=>
  string(0) ""
  ["hardware_keycode"]=>
  int(0)
  ["group"]=>
  int(0)
  ["type"]=>
  int(8)
  ["window"]=>
  NULL
  ["send_event"]=>
  bool(false)
}