Hex dump NSData to String

HexDump.swift

// Thanks http://www.swiftsoda.com/swift-coding/get-bytes-from-nsdata/
func hexDump(data: NSData) -> String {
	var len = data.length
	var s = NSMutableString(capacity: len*2)
	var byteArray = [UInt8](count: len, repeatedValue: 0x0)
	data.getBytes(&byteArray, length:len)
	for v in byteArray {
		s.appendFormat("%02x", v)
	}
	return s
}