* descript.c:

* descript.c:
fixed problem with parsing in match_statistic() causing "DESCRIPTIVE
STAT=MEAN." to barf.
"MEAN" is now default if "SORT" given without specification.
fixed infinite loop with "DESCRIPT GIBBERISH=ALL."
parsing is generally less forgiving of syntax errors: better to have
it do nothing and type it in again then to not know what it actually did instead
 (problem also related to infinite loop problem above).
z-score transformation now check score for user-missing values and ch
ecks std_dev for SYSMIS.