packet mode bios updates -- fixed

[Michael E Brown]

All,
    I found the bug that was preventing BIOS updates in packet mode in
libsmbios <= 0.13.5. I would like to release 0.13.6 really soon with
this fix (tonight or tomorrow), but I really need somebody with an
intel-based mac to tell me if getSystemId works.
--
Michael

PS: bug was an off-by-one error introduced when I ported the code to MS
VS.NET which doesnt support a couple of features gcc does. The structure
size changed by 1, which meant my sizeof() statements needed
adjustments.

PS: I will post the current beta code later tonight for download/test.