Add plugins target to Makefile
Correct case on JingleNodes i18n
Support dialback errors

See XEP-0220, Dialback Errors.

This reduces disconnect in the case of piggybacking errors, and provides better
diagnostics.
Support Dialback Without Dialback

When processing a <db:result/>, this checks for the certificate first. If
this matches, then we don't bother actually dialling back, speeding up the
session setup.

This factors out the certificate verification function.
Log TLS requirement when trying Dialback

If a server requires TLS, it will reject our attempts to verify a dialback
key currently. Log this in the logs rather than (confusingly) ignoring it.
Tidy up outgoing sessions

A few changes here:

1) Don't recurse up the DNS tree. That's just wrong.

2) Also, don't assume that a subdomain is handled by a parent domain's server.
Still wrong.

3) Check certificates post-connect using our new logic, and drop the session
if they don't match and we're not meant to be doing dialback.

4) Do use EXTERNAL if offered, even if we're using a self-signed certificate.
There's no value in not doing so, it's a bizarre behaviour.

5) Disable S2S Compression; it's currently not working. XPP reset seems to fail,
so doing replacement of the input stream instead.

6) Protect against a null features after TLS. Seems unlikely to happen, but
still.
Remove redundant certificate logic in TrustManager

Now subsumed by other checks.
Add TLS/Authentication diagnostics

This adds TLS information and Authentication choices to the server session
details page.

In doing so, it factors out a ServerSession interface, and LocalServerSession
class.
Merge pull request #47 from surevine/s2s-fixes

S2s fixes. Thanks for doing this. I am experimenting with websockets for Openfire s2s and I need these fixes.