define a property's Read/Write interface
in the IRWProp, I=Interface RW=Read/Write Prop=Property
in the (name,type,indtype), name=property name ; type property type ; indtype= index type

for example

if you give IRWProp(Foo,char,int)
then you get
char GetFoo(int) const;
void SetFoo(char,int);
type __declspec(property(get=GetFoo,put=SetFoo)) name[]