Battery Park City had always been one half positive, one half negative. BPC was nice, certainly. It was quiet. It came with a stunning view of the water. The buildings were eco-friendly.And it came with greenery and good landscaping. But it was also dismissed by some as too isolated, too antiseptic and too suburban to compete in this gritty metropolis. In recent months, though, there’s been a surge of restaurants and gourmet markets into Battery Park city — establishing it, finally, as a real neighborhood.