Call checkin() every X seconds.
Call checkin() every X seconds.

/multiThread.abstract.class.php:
	* MAIN:::
		-- new private var, $checkinDelay=1
		-- new private var, $lastCheckin
		-- removed misleading comment.
	* checkin() [NEW,ABSTRACT]:
		-- method to call every second... calling set_checkin_delay() can
		increase this delay.
	* babysitter():
		-- call checkin() if enough time has passed (extra logic to help
		avoid swamping servers).
	* message_handler():
		-- added TODO about putting the output into a log file instead of
		dumping directly to STDOUT.
	* set_max_children():
		-- added TODO (more apparent than the exception in an IDE)
	* get_num_children():
		-- WORKING
		-- returns number of living children
	* set_checkin_delay() [NEW]:
		-- update the checkin delay.

crazedsanity/cs-multiproc,crazedsanity/cs-multiproc