Tile improvement tweaks

My collection of tile improvement tweaks. In summary, these are the changes: - Increased yields for weaker improvements - flexible placement for restrictive improvements - Mountains are valid terrain for adjacency - applied district adjacency to unique districts - added Water Park adjacency when there is Entertainment Complex adjacency - added Neighborhood adjacency when there is City Center adjacency - Forts and other improvements yield Flight Tourism - Unlocked Geothermal Plant earlier but the yields are staggered. - Goody huts appear on more places. Features: 1. Medieval Faires civic allows tile improvements to be built on features: a. Lumber Mill can be built on Rainforest b. Farm can be built on Marsh c. Farm and Plantation can be built on Oasis 2. Sphinx can be built on Marsh. 3. Cahokia Mounds can be built on Marsh. 4. Chateau can be built on Marsh and Floodplains even if not adjacent to a Bonus or Luxury resource. 5. Chateau provides +1 Gold for each adjacent Bonus resource. 6. Chateau provides +1 Culture for each adjacent Luxury resource. 7. Ziggurat can be built on Marsh. 8. Ziggurat provides +1 Science on Education technology. 9. Roman Fort provides +1 Culture 10. Fort, Roman Fort and Pa provide +1 Culture on Castles technology 11. These tile improvements provide Tourism based on Culture after Flight technology: Farm Quarry Camp Lumber Mill Fishing boat Fishery Oil Well Offshore Oil Rig Fort Roman Fort Pa Vampire Castle 12. Antiquity Sites and Shipwrecks provide +1