Kids won’t be the only miserable people during these waning days of summer, when the first day of school lurks like a dour detention officer. The retailers selling students back-to-school clothing, supplies and gadgets will be pretty sad souls too. …Back to school is the second most important season for retailers, behind the December holidays. According to a survey conducted by Beemer, more than half of American parents are trying to get their children to recycle the clothing they wore last year, summer growth spurts not withstanding. More parents are also controlling the purse strings and moving down-market for pants and shoes.