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/error.go

@@ -3,6 +3,7 @@ package stanza
 import (
 	"encoding/xml"
 	"strconv"
+	"strings"
 )
 
 // ============================================================================
@@ -53,10 +54,19 @@ func (x *Err) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
 			}
 
 			textName := xml.Name{Space: "urn:ietf:params:xml:ns:xmpp-stanzas", Local: "text"}
-			if elt.XMLName == textName {
+			// TODO : change the pubsub handling ? It kind of dilutes the information
+			// Handles : 6.1.3.11 Node Has Moved for XEP-0060 (PubSubGeneric)
+			goneName := xml.Name{Space: "urn:ietf:params:xml:ns:xmpp-stanzas", Local: "gone"}
+			if elt.XMLName == textName || // Regular error text
+				elt.XMLName == goneName { // Gone text for pubsub
 				x.Text = elt.Content
-			} else if elt.XMLName.Space == "urn:ietf:params:xml:ns:xmpp-stanzas" {
-				x.Reason = elt.XMLName.Local
+			} else if elt.XMLName.Space == "urn:ietf:params:xml:ns:xmpp-stanzas" ||
+				elt.XMLName.Space == "http://jabber.org/protocol/pubsub#errors" {
+				if strings.TrimSpace(x.Reason) != "" {
+					x.Reason = strings.Join([]string{elt.XMLName.Local}, ":")
+				} else {
+					x.Reason = elt.XMLName.Local
+				}
 			}
 
 		case xml.EndElement: