ProgressivePair = function(dict, options) {
                Pair.call(this);

                this.encoder = new Encoder(dict, true, options);
                this.decoder = new Decoder(dict, true, options);
            }
Constructs a new progressive PSON encoder and decoder pair.
@exports PSON.ProgressivePair
@class A progressive PSON encoder and decoder pair.
@param {Array.<string>=} dict Initial dictionary
@param {Object.<string,*>=} options Options
@constructor
@extends PSON.Pair