IVGCVSW-2697 Add Serialize/Deserialize for the Merger Layer

* Force generation of schema header in every build
* Also fixed typo in OriginsDescriptor comment (Descriptors.hpp)
* Added Serialize/Deserialize check on Addition Layer
* Added Serialize/Deserialize check on Floor Layer
* Added Serialize/Deserialize check on Minimum Layer
* Added Serialize/Deserialize check on Maximum Layer
* Added Serialize/Deserialize check on Multiplication Layer
* Added Serialize/Deserialize check on Division Layer

Change-Id: I1358ea4db7ca506d8bcec2ee64e1fbad6005e723
Signed-off-by: Jim Flynn <jim.flynn@arm.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1dff39f..003c9df 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -150,6 +150,7 @@
 endif()
 
 if(BUILD_ARMNN_SERIALIZER)
+    file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/src/armnnSerializer/ArmnnSchema_generated.h)
     add_custom_command (
         OUTPUT  src/armnnSerializer/ArmnnSchema_generated.h
         COMMAND ${FLATC_DIR}/flatc -o ${CMAKE_CURRENT_BINARY_DIR}/src/armnnSerializer --cpp