Oh, leggings — how we love you. Never has there been such a stretchy, simple, sleek and stylish solution for work, working out, going out on the town, running out quickly to do errands, lounging around the house and even sleeping. Leggings are a faithful and favorite pant — and the fact that they hit every style mark from solid black to colored leather to crazy patterns only adds to the obsession (not to mention the fact that they take up a sliver of the storage space of normal pants, so you can …