Fixed NPC_STONESKIN, NPC_ANTIMAGIC, NPC_MAGICMIRROR and Autocast on magic hit
- Fixed NPC_STONESKIN, NPC_ANTIMAGIC, NPC_MAGICMIRROR (bugreport:6118, bugreport:9375)
  * Using the skills will now be 100% successful (can't be resisted)
  * Fixed skills not working for players (e.g. Ulfhedinn, Mithril Magic Cape, Platinum Shield)
  * Fixed level 5 and 10 not working at all
  * NPC_STONESKIN and NPC_ANTIMAGIC will no longer change DEF/MDEF, instead they will increase/reduce physical/magical damage percentually, this IS official behavior
- Fixed "Autocast on magic hit" having its chance halved (bugreport:9377)