In a decision aimed at easing a longstanding issue, teens in sixth grade and older must now present a student ID card in order to avail themselves of services at Flossmoor Public Library. The move comes after years of complaints by library patrons that some young people who congregate in the upstairs Teen Space are loud, disruptive and disrespectful, according to library Director Aaron Carlin. Carlin said that on weekdays anywhere from 40 to 70 teens, predominantly Parker Junior High students, enter the library after school. Because there are so many students, their groups tend to spill . . .