IPC wall-clock demo
-------------------

I added some printouts to pipes.c so that it would
print the time in microseconds just before the message
is sent, and just after it is received.

That way, all the overhead with forking and the like
can be excluded, and the elapsed time will much better
reflect the time for the message to travel between the
processes.

Usage:

    $ ipc-demo [-v] [MSG]

Examples:

    $ ipc-demo        # send the default "Message: Hi"
    $ ipc-demo -v     # send the default message and be verbose
    $ ipc-demo hi     # send "hi"
    $ ipc demo -v hi  # send "hi" and be verbose