Added support for headers and cookies in WebSocket upgrade request
Added Clear Backlog option
Transferring cookie version into WebSocket initial request cookies.
Setting into cookie manager cookie that may be present in the websocket upgrade response
Remove unused files
Some cleanup
If a sampler reuses a streaming websocket created by some earlier sampler, the new sampler's parameters are picked up
Use CachedThreadPool
Remove files that should have been deleted.
Clean up pom.xml to have reasonable versioning.
Merge remote-tracking branch 'tradingscreen/master'
Added ping support to the WebSocketSampler

* Includes a thread pool for ping handling.
* Can be disabled by setting frequncy to 0
Updated README.md to briefly explain how this differes from the sources
enabled to send multiple frames one by one in a WebSocketSample with
pauses between