Pipe operators

Allow piping files output to file.

Possible syntaxes `;>`, `;>>`, `;|`, `;&&`. It needs to be something that is uncommon, but resembles the standard command line.

Alternatively, provide a way to provide it as a single string, e.g. `-run "cat < alpha.in 2> alpha.out && echo -- alpha.out 2>&1"`. See http://www.tutorialspoint.com/unix/unix-io-redirections.htm.
