Remove clutter from logger (#196)

* Remove clutter from the logger

Prior to this commit the logger was stringfying even functions.
Because of this response errors from axios was dumping a log of info on
the logs.

* Fixing standard style issues

* Check for toString on meta

lib/logger.js

@@ -1,10 +1,15 @@
 const winston = require('winston')
 const options = require('./options')
+const _ = require('lodash')
 
 const logger = new winston.Logger({
   level: options.logLevel,
   transports: [
     new (winston.transports.Console)({ timestamp: true, colorize: true })
+  ],
+  rewriters: [
+    (...[,, meta]) => _.hasIn('toString', meta)
+      ? meta.toString() : 'Error, no further information is available'
   ]
 })