Make afsio be useful on Windows and fix bugs

Make afsio be useful on Windows and fix bugs

On Windows, the stdin and stdout handles default to text
mode which corrupts data piped through them.  At the start
of readFile and writeFile, the mode is now set to binary.

The ProbeUuid callback is supposed to determine if this
client is the same as the one being requested.  Since we
are advertising a new uuid in TellMeAboutYourself and
WhoAmI, we should perform the uuid check and return a
valid answer in order to avoid confusing the file server.

Add support for TellMeAboutYourself.  On Windows, return
valid interface information.

Always print verbose output to stderr.

Display MB/sec to three decimal places.

In readFile, always perform a AFSFetchStatus operation
otherwise we have no idea what the file size is.

On Windows, the path separator is backslash.

Change-Id: I174eda991383301d01fe5d6431d459b6ea01a0be
Reviewed-on: http://gerrit.openafs.org/1930
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Hartmut Reuter <reuter@rzg.mpg.de>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>