[2.3.x] Fix for https://java.net/jira/browse/GRIZZLY-1547 (Enabling compression leads to truncation of files > 16384 Bytes)
 - Only called finished() when we're dealing with the last
    HttpContent chunk to ensure we use the same compression
    context across the entire data set vs individually
    compressing each chunk.
[2.3.x] + fix issue #1549
https://java.net/jira/browse/GRIZZLY-1549
"HttpServletRequest.getServerName() returns null for websocket connection initialization GET requests "
[2.3.x] Incremental changes for https://java.net/jira/browse/GRIZZLY-1546 (Ref GRIZZLY-1345. Generalize the graceful shutdown to be a feature of the core transport vs specific to http-server).
 - Refactoring based on discussions with Alexey.