leaving the quoting up to the success command

[hhaensel]

Maybe, the problem on some machines comes from different usage of quotes in different environments.
I propose to first define the julia script and have the quoting done by the underlying run command of success.
@davidanthoff thanks for your input. I didn't have a computer at hand to test, that's why I was asking for your help.
As David kindly prooved, powershell and cmd need different quotation marks. (Maybe different systems are using different backends? - Well I am speculating ...)
@davidanthoff could you test this version? At least for me it doesn't break things.

EDIT:
This PR refers to the issues #170 and #172 and Nemocas/Nemo.jl#600

[hhaensel]

As quoting was not the problem, I think we can close this