Separate stream creation from XMPP use (client, component, etc).

The address of the server is not necessarily related to the JID, e.g.
DNS SRV lookups, manual configuration, etc. Splitting them up means
there's more control and flexibility over how things are put together.

We can always add convenience funcs later, e.g. something like
DialClient(jid, password), to handle the common case.

client.go

@@ -12,12 +12,20 @@ var (
 )
 
 func main() {
+
 	// Parse args.
 	flag.Parse()
 	jid, _ := xmpp.ParseJID(*jid)
 	password := *password
 
-	x, err := xmpp.NewClientXMPP(jid, password, &xmpp.ClientConfig{InsecureSkipVerify: true})
+	// Create stream.
+	stream, err := xmpp.NewStream(jid.Domain + ":5222")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Configure stream as a client connection.
+	x, err := xmpp.NewClientXMPP(stream, jid, password, &xmpp.ClientConfig{InsecureSkipVerify: true})
 	if err != nil {
 		log.Fatal(err)
 	}

component.go

@@ -7,16 +7,25 @@ import (
 )
 
 var (
+	addr = flag.String("a", "", "Server component address")
 	jid = flag.String("j", "", "JID")
 	secret = flag.String("s", "", "Component secret")
 )
 
 func main() {
 	flag.Parse()
+	addr := *addr
 	jid, _ := xmpp.ParseJID(*jid)
 	secret := *secret
 
-	x, err := xmpp.NewComponentXMPP("localhost:5347", jid, secret)
+	// Create stream.
+	stream, err := xmpp.NewStream(addr)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Configure stream as a component connection.
+	x, err := xmpp.NewComponentXMPP(stream, jid, secret)
 	if err != nil {
 		log.Fatal(err)
 	}

src/xmpp/client.go

@@ -19,13 +19,8 @@ type ClientConfig struct {
 	InsecureSkipVerify bool
 }
 
-// Create a client XMPP stream.
-func NewClientXMPP(jid JID, password string, config *ClientConfig) (*XMPP, error) {
-
-	stream, err := NewStream(jid.Domain + ":5222")
-	if err != nil {
-		return nil, err
-	}
+// Create a client XMPP over the stream.
+func NewClientXMPP(stream *Stream, jid JID, password string, config *ClientConfig) (*XMPP, error) {
 
 	for {
 

src/xmpp/component.go

@@ -7,13 +7,8 @@ import (
 	"fmt"
 )
 
-// Create a component XMPP connection.
-func NewComponentXMPP(addr string, jid JID, secret string) (*XMPP, error) {
-
-	stream, err := NewStream(addr)
-	if err != nil {
-		return nil, err
-	}
+// Create a component XMPP connection over the stream.
+func NewComponentXMPP(stream *Stream, jid JID, secret string) (*XMPP, error) {
 
 	streamId, err := startComponent(stream, jid)
 	if err != nil {