Better dataset validation.

- Update calculation's rules.
- Update tests.
- Add more user feedback.
- Filter out displayed series depeneding on user's selection
- Add figwheel
- Use app state for property details' tab selection: local state is
  reset when something else in the app state changes and the tabs kept
  being set back to Overview.
Set dev to false by default.
Update as per @otfrom's comments.
Merge pull request #490 from MastodonC/feature/better-datasets-ui

Better dataset validation.