Added new high performance HTTP Event Collector (HEC) output adaptor.

[damiendallimore]

With the recent release of Splunk version 6.3 we now have a new high performance data collector called the HTTP Event Collector (HEC), http://blogs.splunk.com/2015/10/06/http-event-collector-your-direct-event-pipe-to-splunk-6-3/

This should now be used over our legacy data collectors which have been available as output adaptors in Spring Integration for some time.

This pull request contains a new output integration adaptor for sending events to Splunk via HEC.

I also refactored the SplunkEvent class which was riddled with legacy logic that is now irrelevant.I also updated the output of the SplunkEvent class to produce simple JSON which is more optimal that KV pairs for Splunk.

Damien Dallimore (Developer Evangelist @ Splunk , ddallimore@splunk.com)

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[artembilan]

Hello, @damiendallimore !

Sorry for delay. We were enough busy with releases for SI core project and other related.
So, now I can switch to your work for review.

[artembilan]

Minor, of course, but that would be better to configure the IDE to add an new line in the end of file.
At least, to avoid such a comments in the future 😄

[artembilan]

So, from big height that's all.
There are a lot to do yet, so let me know your point.

I'd prefer do not do so much re-work myself, because it is your PR, but if you don't have enough time to bring it into mind, that works for us, too.

Thank you for the contribution one more time!

[artembilan]

Closed in favor of #5 .
Sorry @damiendallimore for dropping your PR, but your work is appreciated anyway.

Thank you for the contribution and looking forward for more!