add note about fishy dynamic_cast
add note about fishy dynamic_cast

Change-Id: Icabb2c9574083db73b8d0a40095fa18f84d7d6ab

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core