They never caught the Butcher of Mons, but they found his victims. In 1997, their remains were found, but the case went unsolved and the murders ceased. That is, until today when his two adult children continue the twisted legacy of their father.  Such is the plot of “Megalomaniac,” a gloomy piece of work out of Belgium that won the top Jury Prize for Best Feature at Fantasia last year. From writer/director Karim Ouelhaj, “Megalomaniac” might just be the feel-bad film of the year if, like me, you were lost in the extreme implausibility of “See No Evil.”  But that’s another article.