Start turn with unit selected

Add trigger from building improvements and trigger conditional for building improvements  - By SeventhM

Preparation for multiple required uniques per ruleset object - By dHannasch

Fixed trading with city-state through notifications  - By tuvus

Mention the Railroad production bonus in the Civilopedia  - By Caballero-Arepa

By SomeTroglodyte:
- Notification for "Policy branch unlocked" clickable
- Dev Console: Linting + add Stat