Alex7Kom/node-steam-tradeoffers — pull request #9 by yamalight (2014-06-10 12:24:24+00:00)
Title: Fix for failing on private inventories

Trying to execute loadPartnerInventory() on someone with private inventory crashes everything.
See stack trace of the crash below.
This PR fixes the problem.

```js
TypeError: Object.keys called on non-object
at Function.keys (native)
at mergeWithDescriptions (node_modules/steam-tradeoffers/index.js:136:17)
at SteamTradeOffers. (node_modules/steam-tradeoffers/index.js:94:36)
at Request.self.callback (node_modules/steam-tradeoffers/node_modules/request/request.js:129:22)
at Request.EventEmitter.emit (events.js:98:17)
at Request. (node_modules/steam-tradeoffers/node_modules/request/request.js:873:14)
at Request.EventEmitter.emit (events.js:117:20)
at IncomingMessage. (node_modules/steam-tradeoffers/node_modules/request/request.js:824:12)
at IncomingMessage.EventEmitter.emit (events.js:117:20)
at _stream_readable.js:919:16
```