Let bare King paint itself out of a corner

Let bare King paint itself out of a corner

A bare King now increses the centralization bonus of any square it
visits at game level. This implements a perpetually increasing
'stay-put bonus' for loitering in the same location, and makes the
strong side eventually decide to drive the bare King out of a corner
where it cannot be checkmated.
  This only works in games where the white and black King are defined
as separate piece types (as there is no bare-King recognition otherwise)!