In the receiveMessage and receiveWithContext tests, only ten
milliseconds were allowed for the appender to dispatch the message over
the socket.  Practical experience suggests that on the build system, the
actual latency is on the order of hundreds of milliseconds.  I changed
the allowed wait time to 1000 milliseconds.  This should have little
impact on test duration, as the test will finish as soon as the latch
we're awaiting is updated.

The number of iterations for the loop in lateServerLaunch was derived
from the delay allowed for the appender latch.  The new value for the
delay resulted in an iteration count of one.  I changed this test to
simply use a fixed iteration count.

testConnectionFails was expecting the connector thread to exit after
being interrupted, with latency no greater than the configured delay
between connection attempts.  However, the call to
SocketFactory.createSocket may not return immediately on interrupt.  

Now, we allow 4 * DELAY for the thread to exit. This commit should allow
more than enough tolerance, but (as it generally has no effect on the
run duration of the test) we could increase the allowed delay even
further if it proves too sensitive to timing variations on the build
system.

For consistency with SocketAppender...

Now the focus is on just describing the highlights and deferring
the details to the appropriate chapters of the manual.

Added some language to define "server component" and "client component",
fixed some overall formatting problems, lots of minor fixes and improvements,
added examples of using JSSE system properties, added standard footer.

These were previously in the appenders chapter, now moved to the
receivers chapter, and refined a bit to make them a bit easier to
follow.

Probably want to consider inserting the chapter on receivers
somewhere near the middle...

The Appenders chapter had become quite long due to the inclusion
of the documentation of Receiver components.

This branch refactors the previously contributed "server" and
"remote" components such that they now extend a common "receiver"
component.  A receiver is a component that receives logging
events from a remote appender.  A connection between and an
appender and a receiver may be initiated in either direction;
i.e. a receiver may initiate the connection to an appender or
vice-versa.  The receiver component is configured in Joran using
a <receiver> element.  The class specified in this element
determines whether the receiver will passively await connections
from remote appenders (i.e. as in the legacy SimpleSocketServer)
or whether it will initiate a connection to a remote appender
(a ServerSocketAppender).

Still needs lots of proofreading...

The subclass may need a reference to executor to pass to objects that
will need it later when the receiver is running.