Cookie Handler Class: Store and retrieve serialized variables in cookies

This class can be used to store and retrieve serialized variables in cookies.

It can take an array of values and store its serialized representation in a cookie. It can also unserialized a cookie value to retrieve the original array.

The class can also handle cookies with non-serialized values, as well destroy cookies by setting their expiry date to the past.

This class can also handle switching between non-serialized cookies and serialized cookies.