GXemul Code2

Fix crash for short output.

Minor update.

Copyright year update.

Applying a rather large patch from Jason Thorpe for using /dev/tap devices in addition to the existing networking modes. The patch also consists of enhancements to the DEC21143 and Lance ethernet devices to perform packet filtering.

Do not include X11 specific help if no X11 support is included.

Unfortunately, OpenBSD/sgi will no longer be released after 6.5.

Another kernel to try.

Include cstdio.

Adding Linux for SGI O2 screenshot, and some working URLs.

Minor test machine documentation updates.