code: function(n) {
  		"use strict";
  
  		if (arguments.length === 0) {
  			n = 1;
  		}
  		return this.getDomain(this.jumpDate(this.getDomainKeys().shift(), -n, this.options.domain), 1)[0];
  	}
docs: Get the n-th domain before the calendar oldest (leftmost) domain
  @param  int n
  @return Date The start date of the wanted domain