Improved X509CertificatePanel displaying certificate chain

Changes the X509CertificatePanel to display all certificates (sent by server) in a tree view offering the user to select each certificate to be displayed.
Also makes all certificate text selectable (it is now an editor pane).

Screen shots has previously been discussed in this thread: 
http://lists.jitsi.org/pipermail/dev/2014-May/020793.html

Note/question:
The resource strings (i18n) for the headings should no longer contain tags like "<html><b>" etc, should that be updated via translate.jitsi.org and not in the resource_xx.properties?