Fixed issue with global commands in parent contexts

examples/simple.php

@@ -20,6 +20,29 @@ class MyContext extends Context
      * @command testme
      * @args
      * @help Useful test!
+     * @global
+     */
+    public function test()
+    {
+        echo "Test\n";
+    }
+
+    /**
+     * @command context
+     * @help Create a new context
+     */
+    public function context()
+    {
+        return new OtherContext("newcontext");
+    }
+}
+
+class OtherContext extends Context
+{
+    /**
+     * @command other
+     * @args
+     * @help Other test
      */
     public function test()
     {