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
For ENG-5856, cure cancer of the semicolon and other Steve feedback
For ENG-5856, close the pipe when done
Merge pull request #1189 from VoltDB/ENG-5856

Eng 5856 Keep CMS from ruining your day