Moved cookies to SteamWeb.  As a result:
* SteamWeb is no longer a static class
* Backwards compatibility has been broken.  You now need to pass SteamWeb to Inventory and GenericInventory
* Fetching inventories set to "friends only" should now work.
Merge branch 'WebAndForeignInvImprovements'

Conflicts:
	SteamBot/Bot.cs
	SteamBot/UserHandler.cs