Looped until circuit breaker tripped because `$page` wasn't respected. Also revealed that an additional query was run when we knew it wasn't needed, because we got back fewer entries than we asked for.

When events are cleared with `wp_clear_scheduled_hook()`, they can't be rescheduled until the cleanup job runs.

Fixes #91

Fixes #90

CLI may use this eventually

`get_event()` method was removed earlier

Considerable cleanup and simplification along the way

This logic became spread across various classes during initial development, and it's time to consolidate.

When running events, lookups will be simplified with this already in the DB

Core resets the option before its tests, so we perform the equivalent. Addressing #90 will make the non-Core approach unnecessary.

Updates all of the plugin's core classes to use the new event store, primarily through the helper functions I should've introduced in the first place.

Still need to update tests and CLI commands

Moving out of posts, into a table with appropriate indices and unique key constraints

Improve CPT use and CLI performance