Error handling for failed requests (non 200 codes) (#21)

* added proper error handling to the request to deal with timeouts and other failures based on the format of the responses used in the module

lib/main.js

@@ -70,6 +70,9 @@ function _request_with_backoff (options, body, callback, waitSecs = 1) {
       callback(buffer)
     })
   })
+  req.on('error', (err) => {
+    callback(JSON.stringify({ stat: 'ERROR', message: err.message }))
+  })
   req.write(body)
   req.end()
 }