Allow Robo::register to operate on multiple items (consolidation#1145)

* Allow Robo::register to operate on multiple items

* Oops

src/Robo.php

@@ -513,13 +513,30 @@ public static function process(Process $process)
         return ProcessExecutor::create(static::getContainer(), $process);
     }
 
+    /**
+     * @param \Robo\Application $app
+     * @param string|object $handler
+     *
+     * @return array
+     */
+    public static function register($app, $handlers)
+    {
+        if (!is_array($handlers)) {
+            $handlers = [ $handlers ];
+        }
+
+        foreach ($handlers as $handler) {
+            static::registerSingle($app, $handler);
+        }
+    }
+
     /**
      * @param \Robo\Application $app
      * @param string|object $handler
      *
      * @return null|object
      */
-    public static function register($app, $handler)
+    protected static function registerSingle($app, $handler)
     {
         $container = static::getContainer();
         $instance = static::instantiate($handler);
@@ -548,7 +565,7 @@ public static function register($app, $handler)
      *
      * @return null|object
      */
-    protected static function instantiate($handler)
+    public static function instantiate($handler)
     {
         $container = Robo::getContainer();