Do not respond immediately to the DGI's command

Instead, sleep for one second first. I thought this was being
accomplished with deadline timers, but:

a) The protocol is completely synchronous, so why use complicated
deadline timers when you can just call sleep? and
b) The timers here should have been a member variable -- they're
destroyed after each use, meaning the callback is immediately invoked
with boost::system::error::operation_aborted. And since we don't check
for that, it executes as usual. Ouch.
Remove a couple of extra output statements

Not really sure how verbose we want to be, but I think this is no longer
needed at least.