Make sure the nodejs plugin checks, if all artefacts are installed correctly before executing tasks
Currently the nodejs plugin only checks, whether the nodejs executable exists before executing tasks.
it should also check, if the correct npm version ist installed as well.
fixed in rev d904507
plugin checks, whether node and default npm executable is installed. if one of them is missing, cleans up the nodejs folder and installs node and default npm. after that it checks, whether the specified npm version installed (configured in npm). if not it uses the default npm to install the correct npm version and uses it to perform any npm install tasks.