getting started on datetime deserialization
millisecond and second datetime formats implemented
I commit this just as a testament to how much bullshit ISO8601 is; it's completely wrong code
getting started on a two pass parser for ISO8601 dates
more progress on ISO8601 dates, some times can be parsed now
ISO8601 times finished up, in theory
more pgoress on ISO8601 dates, utc specifier works now
more progress on ISO8601 dates, timezone offsets more or less work; now the bugbear, RFC3339 differs from ISO8601 in meaningful ways but they're both encountered as 'ISO8601' in the wild
testing some error cases when parsing ISO8601 dates
rework some error tests to go through JSON properly, setup more infrastructure for ISO8601 parsing
clean that last test up some