Fixed unidentified command. Fixed erroring.

U2FMessage.cpp

@@ -184,4 +184,5 @@ void U2FMessage::error(const uint32_t tCID, const uint8_t tErr)
 	msg.cid = tCID;
 	msg.cmd = U2FHID_ERROR;
 	msg.data.push_back(tErr);
+	msg.write();
 }

U2F_CMD.cpp

@@ -37,11 +37,13 @@ shared_ptr<U2F_CMD> U2F_CMD::get(const shared_ptr<U2FMessage> uMsg)
 			case U2FHID_INIT:
 				return make_shared<U2F_Init_CMD>(uMsg);
 			default:
+				U2FMessage::error(uMsg->cid, ERR_INVALID_CMD);
 				return {};
 		}
 	}
 	catch (runtime_error& ignored)
 	{
+		U2FMessage::error(uMsg->cid, ERR_OTHER);
 		return {};
 	}
 }