C++11/14

[Hans Aberg]

C++11/C++14 seems to work really well with the compiler I am using (Apple Clang 
on OS 10.10.2): perhaps there might be support for that in the C++ parser, so 
that $$ = x o demand translates into $$ = std::move(x). - The calc++ example 
has lines using std::swap($$, $k), but it would be a bit more efficient with $$ 
= std::move($k) for heavier types than the copy-over type ‘int’ used.