0.6.8

Features:

• add yfc.options.calendar.accept_unexpected_Yahoo_intervals, to stop prompt 'Accept into cache anyway?'

Fixes:

• fix for not knowing day-before close for a newly-fetched dividend
• little bugfix for get_release_dates
• another Pandas TypeError
• GetTimestampNextSession() handles long Chinese holiday
• tweak date printing in verify's debug output