Ported a couple more methods to XS

lib/Slic3r/Config.pm

@@ -340,15 +340,6 @@ sub validate {
     return 1;
 }
 
-# min object distance is max(duplicate_distance, clearance_radius)
-sub min_object_distance {
-    my $self = shift;
-    
-    return ($self->complete_objects && $self->extruder_clearance_radius > $self->duplicate_distance)
-        ? $self->extruder_clearance_radius
-        : $self->duplicate_distance;
-}
-
 # CLASS METHODS:
 
 sub write_ini {