When I try to send POST method using this code:
```
const axios = require('axios')
let config = {url: 'http://{{hostname}}', method: 'post'}
let instance = axios.create(config)
instance.request()
```
It send GET method instead of POST.

I think this line https://github.com/mzabriskie/axios/blob/master/lib/core/Axios.js#L37 should be: `config = utils.merge(defaults, this.defaults, config);`
lib/core/Axios.js
'use strict';
var defaults = require('./../defaults');
var utils = require('./../utils');
var InterceptorManager = require('./InterceptorManager');
var dispatchRequest = require('./dispatchRequest');
/**
 * Create a new instance of Axios
 *
 * @param {Object} instanceConfig The default config for the instance
 */
function Axios(instanceConfig) {