0.5.1

• fix: don't include nameless perk groups in perk groups of perks (#32)
  • This is similar to how nameless perk groups are excluded in the tooltip of perks. The idea is that only perk groups with names can be used as a reference point for the player in the perk tree. Nameless perk groups can be used for other purposes e.g. a custom perk group for enemies.
• fix: remove setting gifted perk as non-refundable (6c688f3)
  • Because it is a refundable perk in vanilla and we don't want to change vanilla behavior.