Version 0.23.2247 - Improve monsters AI

A small update with only one feature: Improve curious AI (now used by thief silme, tickling slime/aspheroid and twinkle). It had two issues: 1) These monsters rushed into starting area too soon and ended up both unnecessarily increasing map difficulty and getting killed and never met on the map further; 2) The chance of being discovered by those in sleep was way too random. Now they try to check the corners which were checked the longest ago, still keeping exploration pattern rather random, it should almost completely fix the first issue and mostly fix the second one. I’m not sure if I want to fix those completely :D, but keep them at lesser level is good.