451634 DefaultServlet: useFileMappedBuffer javadoc is misleading
452246 Fixed SSL hang on last chunk

Back ported refinements from 9.3 to handle empty arrays
453386 - Jetty not working when configuring QueuedThreadPool with minThreads=0.

Fixed by properly initializing the queue capacity and by making sure
that if minThreads=0 at least one thread is always started to handle
the job.
Merged branch 'jetty-9.2.x' into branch 'master'.