ENG-5939: Wait for snapshot sync thread on snapshot close.

Otherwise the channel may be closed before the last sync task runs, then it will
generate an error message.
ENG-5939: Ignore CancellationException when shutting down snapshot sync task.
HTTP client fixes
Updates per Ariel's review
Do not hardcode path to ant executable
Fix ENG-5918
Merge branch 'master' into ENG-2560-good
Optimize the columnInfo to do less redundant work in EE
Merge branch 'master' of github.com:VoltDB/voltdb into innovation-xin-perf-steps
For ENG-5856, improve the old gen GC situation

Make CMS wait as long as necessary to get the young gen GCs necessary to get reasonable pause times.

Eliminate pauses from RMI and add support for disabling JMX entirely.

Set starting heap size to max heap size on Linux when system RAM > 16 gigabytes

Add support for invoking System.gc remotely so that it can be done on a schedule at non-peak times
Merge branch 'master' into ENG-5856
For ENG-5856, check OS reliably before checking total memory
clean up all the column info related sloppy code
Merge branch 'master' of github.com:VoltDB/voltdb into innovation-xin-perf-steps
Merge pull request #1187 from VoltDB/ant-path

Do not hardcode path to ant executable
For ENG-5856, cure cancer of the semicolon and other Steve feedback
Merge pull request #1175 from VoltDB/ENG-2560-good

HTTP client fixes - ENG-2560 and ENG-5438 r=aw
For ENG-5856, close the pipe when done
Merge pull request #1189 from VoltDB/ENG-5856

Eng 5856 Keep CMS from ruining your day
For ENG-6007, raise autho timeout to 30 seconds and make configurable