fix ExpressionMaskParser imports

Author: TomyLobo

worldedit-core/src/main/java/com/sk89q/worldedit/extension/factory/parser/mask/ExpressionMaskParser.java

@@ -27,7 +27,6 @@
 import com.sk89q.worldedit.internal.expression.Expression;
 import com.sk89q.worldedit.internal.expression.ExpressionException;
 import com.sk89q.worldedit.internal.registry.InputParser;
-import com.sk89q.worldedit.math.Vector3;
 import com.sk89q.worldedit.math.transform.Identity;
 import com.sk89q.worldedit.regions.shape.WorldEditExpressionEnvironment;
 import com.sk89q.worldedit.session.SessionOwner;