One thing that Studio Theatre has proven over the past year is that, when necessary, it is unafraid to brutalize its audience. The result has been some of its most ambitious and affecting productions, from the caustic Fat Pig to the harrowing Frozen. The trend continues with the company’s season opener: Red Light Winter, Adam Rapp’s study of an Amsterdam and New York-set love triangle. While the show’s blatant and at times disturbing sexuality may…