The state Education Department has rejected all 15 applications for new charter schools, including 12 in New York City, claiming they failed to meet academic standards. “We always look for quality and these applications didn’t measure up,” Education Department spokesman Dennis Tompkins said Wednesday. “We invited several of the applicants to reapply in June and we gave them suggestions on how to improve their applications.” But charter-school advocates weren’t buying it, saying the rejection of all the applicants reeked of pro-teacher-union politics. “The timing and nature of these blanket rejections should raise serious concerns for New Yorkers ... Mayor de...