Fixed timer implementation

lib/Shell.php

@@ -137,6 +137,7 @@ class Shell
             private $userdata;
             public function __construct($interval, callable $handler, array $userdata) {
                 $this->interval = $interval / 1000;
+                $this->next = microtime(true) + $this->interval;
                 $this->handler = $handler;
                 $this->userdata = $userdata;
             }
@@ -157,9 +158,11 @@ class Shell
      *
      * @param Timer $timer
      */
-    public function removeTimer(Timer $timer)
+    public function removeTimer($timer)
     {
-
+        $this->timers = array_filter($this->timers, function ($v) use ($timer) {
+            return ($v !== $timer);
+        });
     }
 
     public function setPrompt($text)