Got rid of an IntPtr in GetInstalledDepots
Made 'out string' return null on failure
Included Interface version strings for use with ISteamClient
Changed 'ref FriendGameInfo_t' to 'out FriendGameInfo_t'
Added [Flags] and type safty for EPersonaChange
Changed 'CSteamID *' from 'IntPtr' to 'out ulong' / 'ulong[]'
UTF8 support for GetClanChatMessage and GetFriendMessage
Changed 'byte *' from 'ref byte' to 'byte[]'
Fixed errornous callback sizes when dealing with arrays