MLECO-3164: Additional refactoring of KWS API

Part 1
* Add KwsClassifier
* KwsPostProcess can now be told to average results
* Averaging is handlded by KwsClassifier
* Current sliding window index is now an argument of DoPreProcess

Change-Id: I07626da595ad1cbd982e8366f0d1bb56d1040459
diff --git a/source/application/api/use_case/kws/include/KwsResult.hpp b/source/application/api/use_case/kws/include/KwsResult.hpp
index 38f32b4..e0bb868 100644
--- a/source/application/api/use_case/kws/include/KwsResult.hpp
+++ b/source/application/api/use_case/kws/include/KwsResult.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022 Arm Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -47,7 +47,7 @@
             this->m_inferenceNumber = inferenceIdx;
 
             this->m_resultVec = ResultVec();
-            for (auto & i : resultVec) {
+            for (auto& i : resultVec) {
                 if (i.m_normalisedVal >= this->m_threshold) {
                     this->m_resultVec.emplace_back(i);
                 }