Implemented multi-threading for tool extraction. The extraction of the tools is limit...

Implemented multi-threading for tool extraction. The extraction of the tools is limited by a/v software. Without an a/v software interfering, the extraction takes no time (less than a second on the test machine). With an a/v software slowing down things, it can take up to 20 seconds or longer. By extracting several files in parallel, we give the a/v software the chance to take advantage of multi-threading. Should help quite a bit, on multi-core systems.