Update Open Steamworks solution file to VS2012
Update ISteam2Bridge002
Add ISteamAppList001
Add ISteamApps006
Update ISteamController001
Add ISteamFriends014
Add ISteamGameServer012
Add ISteamMusic001
Fix ISteamController001
Fix ISteamMusic001
Add ISteamUGC001
Update ISteamUtils006
Add ISteamUtils007
Update IClientEngine
Update EAppUpdateError
Update ECurrencyCode
Update EParentalFeature
Update EPaymentMethod
Update EResult
Update IClientAppManager