Increase the range at which turf can be placed

[ShadowbirdRH]

Only as much as necessary to fix the minor yet enduring issue of being unable to place turf under objects/structures centered over a tile. A few instances that reliably demonstrate this are the Sunken Boat, Maxwell's Door, and Slanty Shanty.

As it stands, you can remove the turf with a pitchfork, but trying to place a new turf under such an object results in the character continually walking toward/into the object/structure, but never getting close enough to place the turf. In the case of common structures, the solution would simply be to build after editing turf, or destroy and rebuild, but when it comes to indestructible or irreplaceable objects/structures, I know of no legitimate solution. c_speed(70) works, but a non-console solution would be appreciated.