refactor classes into different packages

Author: lbalmaceda

src/main/java/com/auth0/Asserts.java

@@ -2,7 +2,7 @@
 
 import okhttp3.HttpUrl;
 
-abstract class Asserts {
+public abstract class Asserts {
     public static void assertNotNull(Object value, String name) throws IllegalArgumentException {
         if (value == null) {
             throw new IllegalArgumentException(String.format("'%s' cannot be null!", name));