code: function(headers) {
      var cookies = headers['set-cookie']
      if (cookies) {
        cookies.forEach(function(c) {
          var cookiesParams = c.split(';')
          var cookiePair = cookiesParams.shift().split('=')
          var options = {}
          cookiesParams.forEach(function(param) {
            param = param.trim()
            if (param.toLowerCase().indexOf('expires') == 0) {
              var date = param.split('=')[1].trim()
              options.expires = new Date(date)
            }
          })
          this.set(cookiePair[0].trim(), cookiePair[1].trim(), options)
        }.bind(this))
      }
    }
docs: Parses headers from server's response for 'set-cookie' header and store cookie's values.
  Also parses expiration date
  @param headers