Finally. Here in the Northeast the long and oppressive winter is beginning to loosen its grip on our poor, seasonal depression-addled sou ls. The sun is starting to pop out, the open-toe shoes are getting paraded around town, and teachers are starting to feel the restlessness that happens before school's out for summer. If kids think they have it hard, though, they need to get real and start thinking about their teachers. They deserve our pity. By mid-May, they're on the verge of insanity after…