Fix foreign inventory call
Merge pull request #561 from StormReaper/foreigninvfix

Fix foreign inventory call
Generic Trade

TradeUserAssets-related methods and properties improvement
Small fixes

* Updated forgotten handlers.
* Renamed documentation directory.
* Added jsonResponse.IsLoaded = true to GenericInventory.cs when
inventory loads correctly.
Improved: asynchronous load for GenericInventory

Changes:
* Added AsyncGenericInventory.cs
* Fixed display Deserialization errors
* Fixed  not being able to use TradeUserAsset on Inventory.GetItem(...)
Small fixes

Changes:
* Fixed cyclic reference error on Trade.RemoveAllItems*(...) on Trade.cs
.
* Added: Spiral Knights Inventory definition  and Steam Trade Holiday
Sale Definition on Inventories.htm .
* Added public ApiKey, SeesionId and Token on Bot.cs .