A Wisconsin school superintendent who allegedly confined six students in a school bathroom and forced them to strip to their underwear to search for e-cigarettes has been charged with false imprisonment. Suring Superintendent Kelly Casper, 51, was arrested Monday for the Jan. 18 searches, according to online jail records. The six girls, all between 15 and 17, told detectives a similar story: Casper told them to get undressed in the Suring High School bathroom, then checked their legs, bottoms and bras. Two of the girls were allowed to keep their leggings on because they said they weren’t weari…