code: function LRU ( max ) {
  	this.cache  = {};
  	this.max    = max || 1000;
  	this.first  = null;
  	this.last   = null;
  	this.length = 0;
  }
docs: Least Recently Used cache
  
  @constructor
  @param  {Number} max [Optional] Max size of cache, default is 1000