Last year, Sony’s RX100 and RX1 demonstrated the demand for premium performance pocket cameras, positioned at midpoints between cheap point-and-shoots and full-frame DSLRs. Now Nikon’s continuing that march with an option of its own: Coolpix A ($1,100). Rather than picking a tiny or full-frame sensor to stuff in a compact frame, Nikon chose a DX format APS-C sensor with 16.2 Megapixels. And like the RX1, Nikon picked a prime rather than…