Sent acknowledgment when somebody sends us a roster iq.

Revamped how the roster works. We're now using a channel to transmit snapshots of the roster, which is thread-safe. Also found and fixed a bug that was preventing new filters from being sent more than one stanza ever.

Another null change for eol stuff.

Added another BUG comment.

When ranging over an array of structures, the iterand is reused. So storing a pointer to it will cause trouble down the road.

Enabled the Hg eol extension.

Comment fixes.

Nil checks and a greatly simplified filter manager which is less buggy.

Simplified the roster filter.

Fixed up marshaling of the extra fields in presence and message.

Turned off debugging by default.

Implemented roster item delete, and added another BUG comment.

Added roster updating.

Added a stack of filters which can intercept data before it gets to the app.

Comment cleanup.

Making a little more use of XMLName for marshaling instead of having a custom MarshalXML function.

Renamed the somewhat obscure XTo(), etc. to GetTo(), etc.

Made a special-purpose bind structure for resource binding.

Comment cleanup.

Use name tags for roster data structures.

Extended stanzas work now.

Minor fixups to make this come closer to working. It doesn't actually work, though, because the nesting in XML is backwards from how it is in Go. <iq><query/></iq> vs. RosterIq { Iq }

Added a capability to use extensions. There are still some bugs with marshaling involving receiver functions on embedded structs.

Doc and comment update.

Made the namespace constants public.

Added roster retrieval to StartSession().

Make the server's advertised features available to the app.

Made streamError non-public, and made a first attempt at a stream error handler.

Replaced Client.NextId() with a channel named Id.

Don't accept data on Client.Out until resource binding is complete. StartSession() won't do its work until after this happens. That means the app can call StartSession() and wait for it to return before checking Client.Jid.

Added Client.StartSession().

Clarified a comment.