Add gripper module (#3)

src/ModuleFactory.cpp

@@ -20,6 +20,7 @@ std::shared_ptr<Module> ModuleFactory::createModule(
     return std::make_shared<Hub>(device_id, type);
   case ModuleType_SERVO_1:
   case ModuleType_SERVO_2:
+  case ModuleType_GRIPPER:
     return std::make_shared<BoundedPositionalActuator1D>(
         device_id, type, SERVO1_MAX_ANGLE, SERVO1_MIN_ANGLE,
         SERVO1_DEFAULT_ANGLE);