added Boolean return values for loadClass() method

src/Composer/Autoload/ClassLoader.php

@@ -83,12 +83,16 @@ class ClassLoader
      * Loads the given class or interface.
      *
      * @param string $class The name of the class
+     * @return Boolean True, if loaded
      */
     public function loadClass($class)
     {
         if ($file = $this->findFile($class)) {
             require $file;
+            return true;
         }
+
+        return false;
     }
 
     /**
@@ -134,4 +138,4 @@ class ClassLoader
             }
         }
     }
-}
+}