Incomplete data

This might be familiar: a new month rolls in and you get a pit in your stomach. The numbers went down significantly. You look a bit deeper and it turns out they didn't; it's just that the data for this new month is incomplete.
To make this situation clearer, we added some affordance to charts with time-series data for an incomplete month.
Improvements
- Added the ability to partition values in LEAD and LAG functions
- Improved animation performance