Avoid current app from showing up as "???" for others in Friend List + View friends' status

[gf2p8affineqb]

iosu_fpd.cpp, nexFriends.cpp and nexFriends.h are edited to have these changes:

• Starting a friend session on a non-game application (system app, etc) will force myPresence.gameKey.titleId and myPresence.gameKey.ukn to be 0 in order to avoid the app from showing up as "???" for other people in Friend List and instead have no icon just like in real hardware
• Updating the gamemode will force myPresence.gameKey.titleId and myPresence.gameKey.ukn to be the current foreground title id/version (or 0 if not a game app) in order to avoid the app from showing up as "???" for other people in Friend List (the titleid is incorrect when the gamemode is updated, not sure why)
• Renamed nexFriend->gameModeMessage to nexFriend->comment since it is the status comment of an account, nothing to do with GameMode
• When calling NexFriendToFPDFriendData, the gamemode description and status comment from NexFriend will be copied over to FriendData, allowing friends comments and gamemode description to be read in Friend List
• Somewhat implemented GetMyPlayingGame (might be not too accurate)

[gf2p8affineqb]

I forgot to change the other instance of gameModeMessage in nexFriend.readData causing the build to fail, sorry about that!

[Exzap]

thanks!