Fixed threadpool hang and added lots of smoketests.
* Fixed bug in threadpool logic when calling CleanupAnyWorkersSharingAllocator - this was deleting the worker's thread death notifier in the context of a worker thread (which is only allowed from the context of the main thread).
* Added lots more smoketests
* Added --overwrite option to fzip (previously unzipping would always overwrite)
X one
X twoX threeX four
X five
X six
X seven
X eight
X nine
X ten
Before 111
Before 222
Before 333
Match
After 111
After 222
After 333
And so on and so on
And so on and so on