Just in time for the heart of summer (up above the equator, at least), New Balance has released one of the most versatile shoes you'll ever see in any category. The new hybrid Niobium Concept 1 bridges the huge gap between hardwearing waterproof boot and cozy, hut-traipsing slipper ... with another stop along the way. There's no reason to pack extra shoes when you're wearing the newly revived shapeshifter because you already have three different…