wldbg: add flag from which side is message

It's useful when pass has the same function for messages from both
sides.

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
wldbg: start implementing interactive mode

Make interactive mode register its pass and spawn the client. For now,
it has simple (read none) parsing of arguments. Later getopts will be
used.

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
wldbg: wrap invoking passes into function

no comment
dump: nicer dump

Make it a little bit configurable too
saviour