giving feedback when pybuilder is not installed
there is no reason to callback this anymore
DRYing error handling to avoid returns
better error_message rendering
I think this is much more readable
minor refactoring for DRYness
fixing the :shit: before @aelgru sees it
extracting function
minor refactoring
fixing typo and adding possibility to set the pyb path
we need to be aware of the python interpreter because the bootstrapping script in pybuilder does not have the correct shebang
making it work for pybuilder itself