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/CMakeLists.txt b/source/application/api/use_case/kws/CMakeLists.txt
index 517a35a..ea0761c 100644
--- a/source/application/api/use_case/kws/CMakeLists.txt
+++ b/source/application/api/use_case/kws/CMakeLists.txt
@@ -27,7 +27,8 @@
 # Create static library
 add_library(${KWS_API_TARGET} STATIC
     src/KwsProcessing.cc
-    src/MicroNetKwsModel.cc)
+    src/MicroNetKwsModel.cc
+    src/KwsClassifier.cc)
 
 target_include_directories(${KWS_API_TARGET} PUBLIC include)