Clean shutdown of DirPoll when file processing is in progress

[vishnupillai]

DirPollAdaptor does not wait for the dirPoll thread to finish during shutdown. This can cause a dirty shutdown if the dirPoll thread were in the midst of processing a file.
This change makes the shutdown wait for the dirPoll thread to exit in a graceful manner to good extent and then interrupts the thread if still running

[vishnupillai]

@ar Please hold. I'm checking why CI failed.

[vishnupillai]

@ar I've changed a test. Please review and let me know if that causes any issues

[ar]

Vishnu,

Thanks for the PR, but this PR has a merge that could have been rebased, and I'm afraid we'd loose history. In addition, there's a lot of whitespace changes that I'd appreciate if we could make place it in a separate PR or at least a separate commit, it's difficult to tell apart whitespace changes versus the real changed code.

Can you rebase master and re-apply just the DirPoll code fix and its test ?

[ar]

Forget my comment, I can fix this locally.

[vishnupillai]

@ar Thank you. My editor put in some whitespace changes and I tried to revert all the whitespace changes with another commit. Sorry for the multiple commits. The changes may be easier to see if you look at https://github.com/jpos/jPOS/pull/38/files.

[ar]

Exactly, and they installed cleanly when I pulled the pr locally. Sorry for my initial concern, thought a lot more things were changed.

[vishnupillai]

Thanks Alejandro. My over-enthusiasm let to the multiple commits which is not really good. I'm still learning :)