CNPeer/Service refactor

- each CNPeer is given a unique chan *protocol.Event to pass events to
the service.handleEvents() loop. this is now passed to CNPeer.Handler()
as opposed to NewCNPeer().
- service has basically been rewritten. handleEvents() main loop uses
reflect.SelectCase() now to handle all of the eRecv channels for each
peer
- new protocol Event type: EVENT_CLIENT_CONNECT
- Added service_test.go; blackbox-styled testing like the others.
TestService() starts a service and spins up  a bunch of dummy peers
and verifies that each packet sent causes the corresponding packet
handler to be called.

shard/shardserver.go

@@ -19,10 +19,7 @@ type ShardServer struct {
 }
 
 func NewShardServer(dbHndlr *db.DBHandler, redisHndlr *redis.RedisHandler, port int) (*ShardServer, error) {
-	srvc, err := service.NewService("SHARD", port)
-	if err != nil {
-		return nil, err
-	}
+	srvc := service.NewService("SHARD", port)
 
 	server := &ShardServer{
 		service:    srvc,