adding type expressions

Author: Arshia Malkani

src/main/java/net/sf/jsqlparser/expression/operators/arithmetic/Modulo.java

@@ -31,9 +31,6 @@
  */
 public class Modulo extends BinaryExpression {
 
-    public Modulo() {
-    }
-
     @Override
     public void accept(ExpressionVisitor expressionVisitor) {
         expressionVisitor.visit(this);

src/main/java/net/sf/jsqlparser/expression/operators/relational/ExistsExpression.java

@@ -29,6 +29,8 @@ public class ExistsExpression implements Expression {
     private Expression rightExpression;
     private boolean not = false;
 
+    private String expressionType = "None";
+
     public Expression getRightExpression() {
         return rightExpression;
     }

src/main/java/net/sf/jsqlparser/schema/Column.java

@@ -32,6 +32,8 @@ public final class Column extends ASTNodeAccessImpl implements Expression, Multi
     private Table table;
     private String columnName;
 
+    private String expressionType = "None";
+
     public Column() {
     }