- Rename CostForInvalidCell to PathCostForInvalidPath
- Add MovementCostForUnreachableCell
- Update usages of int.MaxValue and short.Maxvalue to use named constants where relevant.
- Update costs on ICustomMovementLayer to return short, for consistency with costs from Locomotor.
- Rename some methods to distinguish between path/movement cost.
Add GrantConditionOn*Layer traits
This allows to
- drop some booleans from Locomotor
- drop a good part of the subterranean- and jumpjet-specific code/hacks from Mobile
- grant more than 1 condition per layer type (via multiple traits)
- easily add more traits of this kind for other layers
