enhance change for test_category made by 8f9b313e

:Release Notes:

:Detailed Notes:
- partial revert of 8f9b313e for test_category.cpp
- change behavior of Service::registerCategory and LS_CATEGORY_END
- re-introduce back macro and direct wrapping of methods from 8f9b313e

:Testing Performed:
unit/integration tests under desktop

:QA Notes:

:Issues Addressed:
[BHV-1592] Implement optional validation of received payload

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>

Change-Id: I7448954a404a23194f66376402e4c16caa62970e
Reviewed-on: https://g2g.palm.com/5505
Reviewed-by: DCO Verification
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Tested-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Reviewed-by: Sergiy Kryvonos <sergiy.kryvonos@lge.com>
Reviewed-by: Alexandr Smoktal <alexandr.smoktal@lge.com>