Stats collection API.

Example usage ''' func main() {

const NUM_CONNECTIONS "num_connections"

sc := stats.NewStatsCollector("test")
sc.AddStatKey(NUM_CONNECTIONS, 0) 
sc.UpdateStat(NUM_CONNECTIONS, 10)
sc.DecrementStat(NUM_CONNECTIONS)

...

fmt.Printf ("Current connections %v", sc.GetStat(NUM_CONNECTIONS)

fmt.Printf(" All stats %v", sc.GetAllStat())

} '''