4.0.2 - Dynamic thread scaling

Changes specific to how new threads are started in the Threaded module. Will spread new thread spawning across 2 minutes if available CPUs exceeds 8. Minimum spawn time is set to 6 seconds during initial filling of cores. After this drops to 2 as it's one in, one out.

If the environment variable PCAP_THREADED_LOADBACKOFF=1 will test the load average. If above the core count will delay a thread from spawning for 30 second periods and re-test.