Remove some unused code

Author: jeffgbutler

src/main/java/org/mybatis/dynamic/sql/SqlBuilder.java

@@ -263,25 +263,21 @@ static StringConstant stringConstant(String constant) {
     }
 
     // functions
-    @SafeVarargs
     static <T extends Number> Add<T> add(BindableColumn<T> firstColumn, BasicColumn secondColumn,
             BasicColumn... subsequentColumns) {
         return Add.of(firstColumn, secondColumn, Arrays.asList(subsequentColumns));
     }
 
-    @SafeVarargs
     static <T extends Number> Divide<T> divide(BindableColumn<T> firstColumn, BasicColumn secondColumn,
             BasicColumn... subsequentColumns) {
         return Divide.of(firstColumn, secondColumn, Arrays.asList(subsequentColumns));
     }
 
-    @SafeVarargs
     static <T extends Number> Multiply<T> multiply(BindableColumn<T> firstColumn, BasicColumn secondColumn,
             BasicColumn... subsequentColumns) {
         return Multiply.of(firstColumn, secondColumn, Arrays.asList(subsequentColumns));
     }
 
-    @SafeVarargs
     static <T extends Number> Subtract<T> subtract(BindableColumn<T> firstColumn, BasicColumn secondColumn,
             BasicColumn... subsequentColumns) {
         return Subtract.of(firstColumn, secondColumn, Arrays.asList(subsequentColumns));

src/main/java/org/mybatis/dynamic/sql/update/UpdateDSL.java

@@ -168,7 +168,7 @@ public UpdateDSL<R> equalToWhenPresent(Supplier<T> valueSupplier) {
 
     public class UpdateWhereBuilder extends AbstractWhereDSL<UpdateWhereBuilder> implements Buildable<R> {
 
-        public <T> UpdateWhereBuilder() {
+        public UpdateWhereBuilder() {
             super();
         }
 

src/main/java/org/mybatis/dynamic/sql/util/InsertMapping.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2016-2017 the original author or authors.
+ *    Copyright 2016-2019 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,12 +15,7 @@
  */
 package org.mybatis.dynamic.sql.util;
 
-import java.util.function.Function;
-
-import org.mybatis.dynamic.sql.SqlColumn;
-
+@FunctionalInterface
 public interface InsertMapping {
-    <R> R mapColumn(Function<SqlColumn<?>, R> mapper);
-
     <R> R accept(InsertMappingVisitor<R> visitor);
 }

src/main/java/org/mybatis/dynamic/sql/util/UpdateMapping.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2016-2017 the original author or authors.
+ *    Copyright 2016-2019 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,12 +15,7 @@
  */
 package org.mybatis.dynamic.sql.util;
 
-import java.util.function.Function;
-
-import org.mybatis.dynamic.sql.SqlColumn;
-
+@FunctionalInterface
 public interface UpdateMapping {
-    <R> R mapColumn(Function<SqlColumn<?>, R> mapper);
-
     <R> R accept(UpdateMappingVisitor<R> visitor);
 }