Updated map and mapgroup macros to get around an rgbds bug.
Legendary beast locale handling annotated and relabeled.
Added a new constant NUM_ENGINE_FLAGS for use in the EngineFlagAction function. This will make it easier for modders to add or remove engine flags.
Updated macros that rely on the GROUP_, MAP_ constants to use the map macro
Added GROUP_NONE and MAP_NONE for the sake of compatibility with this new scheme
Added new macro elevfloor to simplify the definition of elevators under this new scheme