/README.TXT: Full database import: disk space: documented that a higher high-water mark actually occurs later in the import, so that the disk usage issue actually remains a problem after the very beginning

fix: /README.TXT: Full database import: disk space: increased the minimum free space recommendation to 1 TB, because analysis of the disk usage during the beginning of the import shows that actually close to the entire amount is being used. however, this problem is normally undetectable unless the disk space is specifically checked, because it only manifests itself if the available disk space is exceeded completely.

/README.TXT: Full database import: documented that the beginning of the import should be scheduled at a time when the DB will not be needed for other uses, because vegbiendev will be slow for the first few hours of the import due to the import using all the available cores

/README.TXT: Full database import: documented that CPU load warning e-mails can safely be ignored. they happen because the parallel imports use all the available cores.

fix: lib/common.Makefile: $(nice): use an increment of +10 instead of +5 because +5 still leaves the shell sluggish

lib/common.Makefile: added $(nice) and use it everywhere its definition is used

/README.TXT: Full database import: exiting `screen`: clarify that you must use `exit`, as Ctrl+D gets disabled to prevent accidental exits

/README.TXT: Full database import: added step to restart Postgres to free up any disk space used by temp tables from the last import (this is apparently not automatically reclaimed)

/Makefile: postgres_restart-Linux: documented that the manual running of the command is needed because for some reason, pg_ctl does not work when run inside make

fix: /Makefile: postgres_restart-Linux: added pause after telling the user the command to run