logging improvemed, now no longer IllegalArgumentException from Shutdown
Hook Thread, e.g. for StartManyTimes kind of use case.

Signed-off-by: Michael Vorburger <mike@vorburger.ch>
Upgraded commons-exec v1.2 => v1.3, and removed BetterExecutor, as 1.3
includes the fix for https://issues.apache.org/jira/browse/EXEC-69
(Thanks VersionEye)

Signed-off-by: Michael Vorburger <mike@vorburger.ch>
minor - just unused @SuppressWarnings("unchecked"), now no more warnings

Signed-off-by: Michael Vorburger <mike@vorburger.ch>