Implemented the tick handler

lib/Gpio.php

@@ -57,11 +57,13 @@ class Gpio implements \ArrayAccess
         $read = $this->fd_gpio;
         $write = array();
         $except = $read;
-        select($read, $write, $except, 0);
-        foreach($except as $fd) {
-            $pin = $this->getPinFromFd($fd);
-            $pin->doInterrupt();
-        
+        if (count($read)>0) {
+            stream_select($read, $write, $except, 0);
+            foreach($except as $fd) {
+                $pin = $this->getPinFromFd($fd);
+                $pin->doInterrupt();
+            
+            }
         }
     }