The new base category was never meant to be part of the build so the
category makefile was intentionally left off so poudriere and friends
would skip it.

Unfortunately, this idea didn't account for Synth which has a different
behavior: If no category makefile exists, *ALL* subdirectories are
scanned instead of none of them.  (DPorts doesn't use category Makefiles
because by definition all ports are valid; there are no "unhooked" ones)

The proper solution would be to include a practically blank
ports/head/base/Makefile to maintain consistency with the rest of
the ports categories, but synth now actively excludes the base category.

The command output log name has changed from "05_abnormal_cmd.out" to
"05_abnormal_command_output.log".  The former tended to be considered
a binary file by webservers and would download rather than display.

At the end of a bulk run, the final tally (queue size, built, failed,
skipped, ignored) would be displayed in curses mode.  This change adds
the same useful information to the end the main bulk run log.