JSON: Serialize and unserialize values in JSON format

This class can be used to serialize and unserialize PHP variable values in the JSON format (Javascript Object Notation).

It can take a variable value of any PHP type and generates a string that represents that object in JSON format.

The class can also do the opposite, i.e. take a string with a value represented in a JSON format and recreate a PHP variable value of the type defined in the serialized JSON string.