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