* changed hill to terrain Feature
* Update Terrains.json
* Update Terrains.json
* Snow with capital S
* Fixed tests failing
* Added check for ruleset supports hill as terrain feature
* last terrainFeature refactorings
* cut down terrainFeature as much as possible
* aerialDistanceTo fixed
wrapped distance should only be considered on wrapped worlds
* Adding spaces
* fixed tests not compiling
* prevent floodplains from spawning on oasis
* Check if terrain feature can be placed on tile in editor
* Adding reviewed changes
* Unit tests for "canPathThrough"
* Refactoring of canEnterTiles() and isAtWarWith()
* Do not check isEmpty() twice
* Using of the cached MapUnit uniques