Add event or callback if the main runnable event loop fails

[swarwick]

In the package constructor PureJavaSerialPort(String name, int timeout) there is a runnable thread that performs the main read/write operations. If this thread ever fails there is no notification to the end user that is has failed. There should be a COMPLETE event or onCompleteNotifcation callback to let the end user know the main event loop has completed and to check for failures if this occurred at an unknown time vs an actual intended shutdown.

[swarwick]

I just noticed this is a duplicate of issue #108