use reference counter of label
merge refCount_ to definedList2_
test state of @@/@b/@f
remove old @@ from definedList
throw ERR_BAD_LABEL_STR if @f or @b is used
remove old comments
state of @@, @f, @b
remove unused RefCount
template function of hasUndefinedLabel
remove unused string label when outLocalLabel() is called
use suitable name/class
cast to avoid warning
update documents