taskd.pl: eliminate main loop sleep 1 delay

taskd.pl: eliminate main loop sleep 1 delay

Implement a penalty box system where by accept is skipped whenever
the current number of penalty points exceeds a spawning threshold.

The current number of penalty points is increased by one whenever
a new process is spawned and decreased by one as each second passes.

This preserves the previous of accepting no more than one new
connection per second but changes it to no more than one new
connection per second on average while allowing bursts of up to
eight new connections at once.

This improves responsiveness and allows the pipe messages to be
serviced more frequently while avoiding excessive spawning.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>