PubSub protocol support (#142)

* PubSub protocol support
Added support for :
- XEP-0050   (Command))
- XEP-0060   (PubSub)
- XEP-0004   (Forms)

Fixed the NewClient function by adding parsing of the domain from the JID if no domain is provided in transport config.
Updated xmpp_jukebox example

* Delete useless pubsub errors

* README.md update
Fixed import in echo example

* Typo

* Fixed raw send on client example

* Fixed jukebox example and added a README.md

stanza/xmpp_test.go

@@ -2,12 +2,17 @@ package stanza_test
 
 import (
 	"encoding/xml"
+	"errors"
+	"regexp"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
 	"gosrc.io/xmpp/stanza"
 )
 
+var reLeadcloseWhtsp = regexp.MustCompile(`^[\s\p{Zs}]+|[\s\p{Zs}]+$`)
+var reInsideWhtsp = regexp.MustCompile(`[\s\p{Zs}]`)
+
 // ============================================================================
 // Marshaller / unmarshaller test
 
@@ -63,3 +68,14 @@ func xmlOpts() cmp.Options {
 	}
 	return opts
 }
+
+func delSpaces(s string) string {
+	return reInsideWhtsp.ReplaceAllString(reLeadcloseWhtsp.ReplaceAllString(s, ""), "")
+}
+
+func compareMarshal(expected, data string) error {
+	if delSpaces(expected) != delSpaces(data) {
+		return errors.New("failed to verify unmarshal->marshal. Expected :" + expected + "\ngot: " + data)
+	}
+	return nil
+}