Specify a maximum limit for automatic restarts

Our particular use-case requires that JSVC not automatically restart the daemon if the child process throws a fatal error (e.g. OutOfMemoryError - resulting in a dead daemon) or similarly the JVM aborts (bug etc.).

In any case the attached patch goes slightly further and provides a '-restarts n' option which can be set to:
-1 (infinite, also the default and mirrors existing behaviour)
0 (one-shot mode) up to (MAX_INT-1) fixed restart count and specific to the platform.

The patch is just an example of how it could be done.
Note that the intention here is to limit the restart count for successive fatal errors - not for controlled restarts initiated by the administrator via a signal, which actually resets the counter