Add a sortable output mode

[Freaky]

It should be possible to filter output through sort and get reasonable results, in order to find the lines that took longest to appear. Ideally this mode will be selected automatically if stdout/stderr isn't a tty.

tcpdump -ttt probably has the right idea: hh:mm:ss.μsμsμs.

A more general approach to formatting would be nice, but beyond the specific scope of this issue.

[Freaky]

Reopen this, since it still needs work.

[Freaky]

Eh, it's close enough.

The exit line could do with a line duration, but that's both awkward with the current implementation and has indeterminate semantics since stdout and stderr have separate timers and exit's not really tied to either.