Parse for tz from the right in zone(), fixes #1336
Make parseZone() use the format-specified timezone if available
Add test for parseZone TZ inference case
Support 2-digit HH timezones as valid ISO 8601 (fixes #1357)
Merge pull request #1347 from pimterry/fixZoneParsing

Fix zone parsing in potentially ambiguous cases (fixes #1336)
Make colon in ISO timezone format acceptable only when minutes are specified (+01:00 good, +01: bad)
Merge pull request #1358 from pimterry/supportIsoMMTimezones

Support 2-digit HH timezones as valid ISO 8601 (fixes #1357)