old_contents: var Virwox = require('..');
  var util = Virwox.BasicApiUtil;
  
  util.getBitcoinRate().then(console.log)
  
  
new_contents: var Virwox = require('..');
  var util = Virwox.BasicApiUtil;
  var Promise = require('bluebird');
  var fx = require('yahoo-currency');
  
  Promise.all([
      fx.fullRate(),
      util.getBitcoinRate()
  ]).spread(function(c,b){
      b['BTC/JPY'] = b['BTC/USD'].map(function(v){return v * c['USDJPY']});
      return b;
  }).then(console.log)
  
  
subject: add jpy rate