Improve performance of various commands/actions

- Add chunk preloading to RegionVisitor if supplied with a suitable Extent
 - Where extents are used in masks, set EditSession as the extent as they are otherwise initialised with WorldWrapper that is very slow
 - Fixes #1073

worldedit-core/src/main/java/com/sk89q/worldedit/command/BiomeCommands.java

@@ -177,7 +177,9 @@ public class BiomeCommands {
         if (mask != null) {
             replace = new RegionMaskingFilter(editSession, mask, replace);
         }
-        RegionVisitor visitor = new RegionVisitor(region, replace);
+        //FAWE start > add extent to RegionVisitor to allow chunk preloading
+        RegionVisitor visitor = new RegionVisitor(region, replace, editSession);
+        //FAWE end
         Operations.completeLegacy(visitor);
 
         player.print(Caption.of(