Implement xep-0245 (xmpp). Closes #1137 (#1144)

bridge/xmpp/xmpp.go

@@ -70,12 +70,19 @@ func (b *Bxmpp) Send(msg config.Message) (string, error) {
 	if msg.Event == config.EventMsgDelete {
 		return "", nil
 	}
+
 	b.Log.Debugf("=> Receiving %#v", msg)
 
 	if msg.Event == config.EventAvatarDownload {
 		return b.cacheAvatar(&msg), nil
 	}
 
+	// Make a action /me of the message, prepend the username with it.
+	// https://xmpp.org/extensions/xep-0245.html
+	if msg.Event == config.EventUserAction {
+		msg.Username = "/me " + msg.Username
+	}
+
 	// Upload a file (in XMPP case send the upload URL because XMPP has no native upload support).
 	if msg.Extra != nil {
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {