add more Constants

src/main/java/com/olexyn/tabdriver/Constants.java

@@ -3,4 +3,9 @@ package com.olexyn.tabdriver;
 public interface Constants {
 
 	String EMPTY = "";
+	String BUTTON = "button";
+	String INPUT = "input";
+	String ID = "id";
+	String TABLE = "table";
+	String DIV = "div";
 }