Fix building snap misaligning view

field item coordinates need to be even, not odd
do the same "even" clamp

(we do this so that we can sync the terrain tile view to the field item view)

NHSE.WinForms/Subforms/Map/FieldItemEditor.cs

@@ -779,7 +779,9 @@ private void LoadIndex(int index)
             // -32 for relative offset on map (buildings can be placed on the exterior ocean acres)
             // -16 to put it in the center of the view
             const int shift = 48;
-            View.SetViewTo(b.X - shift, b.Y - shift);
+            var x = (b.X - shift) & 0xFFFE;
+            var y = (b.Y - shift) & 0xFFFE;
+            View.SetViewTo(x, y);
         }
 
         private void NUD_BuildingType_ValueChanged(object sender, EventArgs e)