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)
=head1 FShell Documentation
L<Introduction|fshell::commands::fshell/Introduction> - an introduction to fshell.
L<Getting started|getting_started> - a guide to getting fshell up and running on various different platforms.
L<Change History|fshell::change_history>
L<Core FShell functionality|core>
L<FShell Commands|commands> - an A to Z of all the commands that fshell supports.
L<Plug-ins|plugins>
L<Developer documentation|internal> - documentation for developers wishing to extend fshell or write new commands.