0.6

• removing the tutorial to a separate repo
• adding windows tests to codecov
• accepting None as a valid output from a FunctionTask, also for function that returns multiple values
• fixing slurm error files
• adding wf._connection to checksum
• allowing for updates of wf._connections
• editing output, so it works with numpy.arrays
• removing to_job and pickling task instead (workers read the tasks and set the proper input, so the multile copies of the input are not kept in the memory)
• adding standalone function load_and_run that can load and run a task from a pickle file
• removing create_pyscript and simplifying the slurm worker
• improving error reports in errors flies
• fixing make_class so the Output is properly formatted