ob-powershell fixes, looking for original author

[Monstara]

Hello, I found an incomplete implementation of ob-powershell and fixed it.

However, the original did not have a license, so it is not possible to proceed further, e.g. put it up on melpa.

Is the original author here on the list? I think they do not have a contact address on github. Also posted on reddit to no avail.

Regards,

Mois