[Improve] enhance all melee weapon — Last Hopeless Steam update #709835

Small update, melee wepaon is too weak, just add a pain killer buff for them. the melee weapon now will recover some health(maximun of 2) when the player lost heath every 3 seconds(will not recover health if no damage taken). - fix description of chair - improve zombie generation logic, more new zombie will be random generated - Add pain killer for melee weapon, will recover some health when you lost health(maximun of 2 per 3 seconds)