Make start/end dates optional.
Add date comparators.
Add URL helper support for /list endpoint.
Add seasonal hour-of-day line chart.
Fix support for regenerating chart (after toggling sources on/off).
Remove unused buttons.
Adjust season colors when hemisphere changes.
Remove unused code.
Integrate seasonal hour-of-day chart.
Add button to pause chart swap.
Add keyboard support for space (toggle auto swap), left arrow (previous chart) and right arrow (next chart).
Fix typo.