must call super.start() in ServerSocketAppenderBase

Duh.
ServerSocketAppenderBase must invoke super.stop()

Duh.
improved logging in RemoteLoggerStreamClient
improved logging in ConcurrentServerRunner
removed stray diagnostic println
removed some assertions from run method
added ServerSocketAppender classes
updated DefaultNestedComponentRules to handle SSLServerSocketAppender

SSLServerSocketAppender has an "ssl" property of type SSLConfiguration.
Merge pull request #94 from ceharris/LOGBACK-823

LOGBACK-823: add ServerSocketAppender classes to classic