Fixed AIOOBE and a missing return, removed an unused and ambiguous method from CommandContext.

src/main/java/com/sk89q/minecraft/util/commands/CommandContext.java

@@ -221,10 +221,6 @@ public class CommandContext {
         return Double.parseDouble(value);
     }
 
-    public int length() {
-        return args.length;
-    }
-
     public int argsLength() {
         return args.length - 1;
     }

src/main/java/com/sk89q/worldedit/commands/SelectionCommands.java

@@ -585,8 +585,9 @@ public class SelectionCommands {
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
 
-        if (args.length() == 0) {
+        if (args.argsLength() == 0) {
             session.getRegionSelector(player.getWorld()).clear();
+            return;
         }
         String typeName = args.getString(0);
         if (typeName.equalsIgnoreCase("cuboid")) {