Optimize experience after Lv.40 — BioKept Steam update #1349510

Adjust the interaction between toxin damage and evasion. Lightning damage now no longer has a 25% chance to deal damage based on max HP; instead, it now always partially penetrates defense. Modify arena challenge logic. Now, failing a challenge will reduce the hidden matchmaking rating (MMR) for arena opponents. Arena battles now have a chance to drop creature banners, which improve performance when fighting against that specific creature type. Revise Star Sea challenge logic. The Star Sea now consists of only one map. Instead of dropping creature genes, the Star Sea now drops skill books. These skill books can be used, within certain restrictions, to directly add a skill to a creature, replace an existing skill, or upgrade a skill's level. Rework the post-level-40 experience. The experience curve for creatures after level 40 has been adjusted. New equipment tiers have been added for lev...