Small update of WikiBot tweaks

Just a small udate today with a few tweaks to the recently introduced "VS WikiBot" mode!

• WikiBot's difficulty now goes up to MK 25 (instead of 20) for those out there looking for an extremely good opponent!
• You can now manually set WikiBot's rank. It still goes up and down depending on your results when playing against it, but the manual setting should help in case you want to skip a few ranks, or to pick things up where you left them when you are playing on a new device (or lost your save file).
  
• Bugfix: If "VS WikiBot" was the first thing you ever played in the game, the bot would always be wrong for its first few guesses on its starting rank. Now it starts with a chance of being correct slightly above 50% by default (on "MK 1").

With many hard-fought duels on my own way up the ladder, the new mode has quickly become one of my absolute favorite ways of playing WikiArena! I hope you enjoy it as as much as I do! :)