Improve difficult terrain rules

[alice-i-cecile]

What problem does the current design create?

Rounding down or reducing by one causes strange edge cases with forced movement.

What solution would you like?

Forced movement reduced by half, rounded up.

What alternative(s) have you considered?

No effect on forced movement.

[sixfold-origami]

It has weird edges with regular movement as well. Difficult terrain is applied if you're leaving a DT tile, right?

[alice-i-cecile]

Fixed in 4c3e851.

[alice-i-cecile]

Nope, still broken. If you move into difficult terrain while adjacent, you lose 1 tile of movement.

Storing "tiles of movement" or some other form of cross-action state is the only solution.

[alice-i-cecile]

Done.