Simplify time options

These 3 'Emergency' options are not suitable fo end-users. Nobody
understands what they do, apart from those who delved into the code.

For end-users, only one option should be required to adjust for lag. This
is also more consistent with what other engines do.

As for Move Horizon, I see no reason to change its value. Seems better to
hardcode it as 40, and tune the Emergency Move/Base Time instead.

No functional change.