ipc changes

Both the logd and nt projects make changes to ipc.cc

I've nearly finished preparing a stylistic change to ipc.cc to make both
projects have significantly smaller deltas... based on the object
arrangement in the nt code base today.

I'll import this in a day or so, unless there are objections. I haven't
got a separate branch for it - the external_logger branch will have the
closest patch (it will be that branch's ipc changes minus the OneWay
helper style).

Rob