WaE: unused function 'isString'
WaE: unused function 'isString'

Change-Id: I991cbf4a0203debaa98887d2db3fec9654dc1c5b

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