A basic url-shortener. Provide a unique set of characters to convert from and to. Basically a base conversion.
Use: Connect the class to a database by implementing the methods in the DAO class. The database should provide a primary key, a field to store the shortened url, and the original url.
Instantiate the DAO class, and pass it into the URLShortenerFactory.
Possible todos: Make it work for international characters. Add error handling.