Rationalize example JVM parameters.

Add additional sensible example parameters:
  -XX:+PrintPromotionFailure
  -XX:+PrintFlagsFinal
  -XX:+PrintFlagsInitial

Explain that default heap size is dynamically calculated to avoid
confusion with example hard-coded sizes.

Remove legacy parameters that don't apply anymore, such as:
  wrapper.lockfile
  wrapper.java.app.mainclass
RRD using wrong scheduler thread fixed, closes #1746
Shell: Print a warning when exiting with unterminated input
Merge pull request #1750 from jakewins/fix-rrd-shutdown

RRD using wrong scheduler thread fixed, closes #1746
Merge pull request #1731 from apcj/jvm-args

Rationalize example JVM parameters.
Merge pull request #1757 from chrisvest/shell-warn-unterminated

Shell: Print a warning when exiting with unterminated input