Greer Hall reckons there’s a bit of madness in every boxer. The 20-year-old from Cambridge, one of seven Kiwi fighters headed to the Glasgow Commonwealth Games, tried out a few sports before finding the one that matched her restless streak. Hall had quit the rough-and-tumble BMX – where she was a world titleholder and New Zealand age-group representative – when she started Cambridge High School. Her older brother and training partner, multiple n…