javadoc tweek, SuppressWarnings about thread sleeping in loop (so that programs employing it don't get deprecation warnings)

fix threading/race condition causing intermittent socket errors by refactoring socket creation from send/receive threads, synchronized to avoid interleaved reentry

improvements to PduRecorder self-test diagnostics, documentation and variable naming; example .dislog output

for both send/received. Modeled after DMg's efficient 
BehaviorProducerUDP