Some region selection fixes

- CuboidSelection no longer deals with IncompleteRegionExceptions
- Fixed Polygonal2DSelection not passing its region to the selector
- Fixed Polygonal2DRegion not cloning the list it receives in its constructor
- Gave PolygonalRegionSelector a new constructor where it takes a list of points

src/main/java/com/sk89q/worldedit/bukkit/selections/CuboidSelection.java

@@ -21,7 +21,6 @@ package com.sk89q.worldedit.bukkit.selections;
 
 import org.bukkit.Location;
 import org.bukkit.World;
-import com.sk89q.worldedit.IncompleteRegionException;
 import com.sk89q.worldedit.Vector;
 import com.sk89q.worldedit.bukkit.BukkitUtil;
 import com.sk89q.worldedit.regions.*;
@@ -37,6 +36,7 @@ public class CuboidSelection extends RegionSelection {
     public CuboidSelection(World world, Vector pt1, Vector pt2) {
         super(world);
 
+        // Validate input
         if (pt1 == null) {
             throw new IllegalArgumentException("Null point 1 not permitted");
         }
@@ -45,16 +45,17 @@ public class CuboidSelection extends RegionSelection {
             throw new IllegalArgumentException("Null point 2 not permitted");
         }
 
+        // Create new selector
         CuboidRegionSelector sel = new CuboidRegionSelector(BukkitUtil.getLocalWorld(world));
+
+        // set up selector
         sel.selectPrimary(pt1);
         sel.selectSecondary(pt2);
 
-        try {
-            cuboid = sel.getRegion();
-        } catch (IncompleteRegionException e) {
-            throw new RuntimeException("IncompleteRegionException unexpectedly thrown");
-        }
+        // set up CuboidSelection
+        cuboid = sel.getIncompleteRegion();
 
+        // set up RegionSelection
         setRegionSelector(sel);
         setRegion(cuboid);
     }

src/main/java/com/sk89q/worldedit/bukkit/selections/Polygonal2DSelection.java

@@ -41,13 +41,17 @@ public class Polygonal2DSelection extends RegionSelection {
         super(world);
         LocalWorld lWorld = BukkitUtil.getLocalWorld(world);
 
+        // Validate input
         minY = Math.min(Math.max(0, minY), world.getMaxHeight());
         maxY = Math.min(Math.max(0, maxY), world.getMaxHeight());
 
-        Polygonal2DRegionSelector sel = new Polygonal2DRegionSelector(BukkitUtil.getLocalWorld(world));
-        poly2d = new Polygonal2DRegion(lWorld, points, minY, maxY);
-        sel.learnChanges();
+        // Create and set up new selector
+        Polygonal2DRegionSelector sel = new Polygonal2DRegionSelector(lWorld, points, minY, maxY);
 
+        // set up CuboidSelection
+        poly2d = sel.getIncompleteRegion();
+
+        // set up RegionSelection
         setRegionSelector(sel);
         setRegion(poly2d);
     }

src/main/java/com/sk89q/worldedit/regions/Polygonal2DRegion.java

@@ -76,7 +76,7 @@ public class Polygonal2DRegion implements Region {
      * @param maxY
      */
     public Polygonal2DRegion(LocalWorld world, List<BlockVector2D> points, int minY, int maxY) {
-        this.points = points;
+        this.points = new ArrayList<BlockVector2D>(points);
         this.minY = minY;
         this.maxY = maxY;
         hasY = true;

src/main/java/com/sk89q/worldedit/regions/Polygonal2DRegionSelector.java

@@ -80,6 +80,12 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIRegion {
         }
     }
 
+    public Polygonal2DRegionSelector(LocalWorld world, List<BlockVector2D> points, int minY, int maxY) {
+        final BlockVector2D pos2D = points.get(0);
+        pos1 = new BlockVector(pos2D.getX(), minY, pos2D.getZ());
+        region = new Polygonal2DRegion(world, points, minY, maxY);
+    }
+
     public boolean selectPrimary(Vector pos) {
         if (pos.equals(pos1)) {
             return false;