(parser_control): rels_seen is now a boolean, not a

(parser_control): rels_seen is now a boolean, not a
count, since there's no maximum.  All uses changed.
Add member dsts_seen.
(local_zone): Accumulate dsts_seen rather than relying on tm_isdst
not being INT_MAX.
(get_date): Initialize dsts_seen, and check that it doesn't go over 1.
Use pc_rels_seen to decide whther a date is absolute.

(number): Don't overwrite year.
(get_date): Initialize pc.year.digits to 0, not 4, to enable above check.