BOOST_VMD_TUPLE_PUSH_BACK — appends an element to the end of a tuple.
// In header: <boost/vmd/tuple/push_back.hpp> BOOST_VMD_TUPLE_PUSH_BACK(tuple, elem)
tuple = tuple to to append an element to. elem = element to append.
If the tuple is an empty tuple the result is a tuple with the single element. Otherwise the result is a tuple after adding the element to the end.
