Implemented lifecyle and appender methods, and added unit tests and
supporting classes.

Previously only the queue size was exposed.  Having the queue itself
exposed for configuration makes it easier to write a unit test that
isn't overly complicated.

The stop method was iterating a copy of the collection.  Since this is
exactly what accept(ClientVisitor) does, stop can simply delegate to
accept with a visitor that closes each visited client.

This method will allow a user of a ServerRunner to visit each of the
connected clients in order to do something with the client.

When the ConcurrentServerRunner is moved to core, it cannot reference
directly the Logger and LoggerContext objects.  Now the base class
delegates its logging to a subclass.

The javadoc references to SocketRunner will cause an unwanted important
when this interface is moved to core.

The ServerListener was converted to use a type parameter for the Client
subtype.  The Client interface was stripped down and the
remote-appender-specific methods were moved to a subinterface.  These
changes allowed the ConcurrentServerRunner and ServerSocketListener to
use a generic Client and to be reworked to move all of the
remote-appender-specific code to subclasses.  With these changes the
abstract base classes and interfaces can be moved to core to support
other server types.

In ConcurrentServerRunner, after the LoggingContext is resolved,
informational and error messages logged by the server should no longer
be written to the StatusManager associated with the underlying Context
passed to the runner during configuration.

The references replaced should have been referring to the interface,
not the concrete implementation.  This is just a left over from the
rename-concrete-class/extract-interface refactoring sequence not
handled automatically by the refactoring tool.

Notice during copy and paste testing of the examples.

This is for consistency with the JDK documentation and system properties.

These edits integrate the documentation for SSLSocketAppender with
SocketAppender, taking advantage of the similarities of configuration
and examples.