Show one more perk when leveling up.

Tips

• Bookworm is best selected on earlier floors, but is still useful later on.
• As more and more perks are unlocked, this perk becomes critically important in being able to pick perks that are actually useful.
• Saiph, the Librarian starts the game with the Bookworm perk. This allows him 3 perks to pick between the entire game to help make up for the fact he levels slower.