- get_terrain and set_terrain replaced with direct indexing operations
- get_map_size mostly replaced with either the iterator or an on_board call.
Only a few cases really needed to know the size of the map for some other purpose.
- shroud and fog operations, village owner, time areas, and location filters
- get_terrain_info replaced with terrain_types table
- Map generation functions create_map and create_filter
The ai_helper functions are optimized for speed (as much as possible in a general setting) and do all the necessary tests. For example, get_units_with_attacks() checks both whether the unit has attacks left, and whether it has any attacks in the first place.
(cherry-picked from commit 75843541bcf92e743b911ef49046c54a050e8a0f)
