Fixed issue with global commands in parent contexts

lib/Context.php

@@ -71,7 +71,7 @@ class Context
             }, explode("\n", $docblock));
             $info = [];
             foreach ($lines as $line) {
-                if (preg_match("/^@(command|help|args) (.+?)$/", $line, $match)) {
+                if (preg_match("/^@(command|help|args|global)\\s*(.*)$/", $line, $match)) {
                     list($void,$key,$value) = $match;
                     $info[$key] = $value; 
                 }
@@ -132,6 +132,12 @@ class Context
         return $ret;
     }
 
+    public function isCommandGlobal($command)
+    {
+        $info = $this->commandInfo[$command];
+        return array_key_exists('global', $info);
+    }
+
     public function getName()
     {
         return $this->name;