Can now resume sweeps that end early
Can now resume sweeps that end early, also the copied sweep configs are now saved with a standard name sweep_config.yaml
The current logic is a little strange as the sweep run function will continue if it is passed a result_dir - so the logic depends on the existence of a result_dir. Not sure of a better way around this.
Also there is a known bug - if the sweep that is being continued ended mid task - that task will have ended with an error and so will not be picked up as an unfinished task and hence, not rerun in the continue.