Release 12.0.0

Feature: Updated to Steamworks SDK 1.42
Feature: Improved support for 2017.3-2018.3
Feature: Automatically disabled on non-Steam supported platforms

Fixed: ISteamInventory_SetProperty overloads no longer all point to the same native method.

The prebuilt "Standalone" package is for non-Unity .NET applications ONLY.
Get the .unitypackage if you are using Unity.