- Refactored EventsLoader and BlazeEventsLoader to not require a
subclass per dataset. Instead, you now pass a map from columns to
event fields directly to the EventsLoader constructor.
- Removed a large number of Quantopian-specific datasets and associated
tests.
- Rewrote the core logic of EventsLoader and BlazeEventsLoader to share
index calculations across multiple requested columns.
- Fixed a bug where event fields were incorrectly forward-filled when
null values were present in an event.