minor: typo
TODO
WIP: TileAnimation Fixes

A couple of things:

- When new times are loaded, refreshes the current layer,
  instead of going back to Date.now()
- Improved handling of transitions with non-yet-loaded layers.
  - Move isLoaded logic to transition method
  - If a layer isn't loaded, show it once it does load
  - Set the layer to the map, to trigger loading.
TODO