Fix typos (2nd acst should have been acdt), 0550 for ist should be 0530
(5.5 hours is not 5 hours and 50 minutes...).
Comment out the zp4 zp5 and zp6 zone names. They are supposedly supported
by the source (they're in the table) but cannot work, as the parsedate
lexer doesn't allow a "word" to start with an alpha and also contain
digits. Maybe (just maybe) that could be fixed sometime, but since these
have never worked, and no-one has ever seemed to miss them, and they're the
only words which are of that form, for now, just stop pretending they work.
53e5e3df7a