Add VALUE_TYPE operator

m-array.h

@@ -77,6 +77,7 @@
    ,IT_REMOVE(M_C(name,_remove))                                        \
    ,CLEAN(M_C(name,_clean))						\
    ,KEY_TYPE(size_t)                                                    \
+   ,VALUE_TYPE(M_C(name, _type_t))                                      \
    ,SET_KEY(M_C(name, _set_at))                                         \
    ,GET_KEY(M_C(name, _get))                                            \
    ,M_IF_METHOD(INIT, oplist)(GET_SET_KEY(M_C(name, _get_at)) ,)        \