Description:
------------
Event seems to segfault when given an unexisting fd or php://temp

Test script:
---------------
<?php

$base = new EventBase();
$input = fopen("php://temp", "r+");

$event = new Event($base, $input, Event::READ, function ($fd, $events, $arg) {
    echo "OK";
  });

$event->add();
$base->loop();

?>

Expected result:
----------------
OK

Actual result:
--------------
HP Warning:  Event::__construct(): fcntl: invalid file descriptor passed in 
/Users/andrey/react/eventTest.php on line 8
PHP Stack trace:
PHP   1. {main}() /Users/andrey/react/eventTest.php:0
PHP   2. Event->__construct() /Users/andrey/react/eventTest.php:8

Warning: Event::__construct(): fcntl: invalid file descriptor passed in 
/Users/andrey/react/eventTest.php on line 8

Call Stack:
    0.0002     241160   1. {main}() /Users/andrey/react/eventTest.php:0
    0.0005     246032   2. Event->__construct() 
/Users/andrey/react/eventTest.php:8

Segmentation fault: 11