Fix for changed game URLs in stats data
Fixed broken string interpolation in SteamGame#logo_thumbnail_url
Made SteamGame immune to apps with no image

Fixes koraktor/steam-condenser#167
Deprecated hackish master server functionality
Improved failover handling for master servers

Fixes koraktor/steam-condenser#116
Added method to disconnect servers

This is necessary to clean up Source servers with open RCON connections.
Detect RCON sockets in CLOSE_WAIT state

Instead of RCONBanError this triggers a reconnection. Please note, that
the connection has to be reauthenticated afterwards.

See koraktor/steam-condenser#169
Fixed RCONSocket tests
Removed old attribute readers for favorite game in SteamId
Added "withgod" to contributors
Raise RCONNoAuthError when applicable
Automatically retry if RCON socket is closed during #rcon_auth

See koraktor/steam-condenser#169
DotA 2 items don't have a slot
Added support for the ISteamUser/ResolveVanityURL Web API
Added debug output to WebApi#load
Added debug output to RCONSocket#reply
Require steam_id in game_inventory
Link GameItems to their GameInventory
Rename GameItem#class to GameItem#item_class

We don't want to override Object#class.
Add tests for ISteamUser/ResolveVanityURL API