Adds a mechanism (which was added to KafkaEventStreamDecoder
incorrectly) to print the exception to help flush out our flakey tests.

See commit 92455e43 - which is the same changes in
KafkaEventStreamDecoderTest for details

Runs clang-tidy pass by ref across the codebase to fix-up various
warnings we are seeing in cppcheck

Also updated class_maker.py

This commit replaces all header guards in LiveData with #pragma once

This was replaced wholesale recently but missed in a new file
that was created and merged after the changes.