[Do not merge. under discussion] node global installation fix

Discussion is going in #131 
> And where should I put ldconfig -p | grep cairo in the script? sorry I am quite newbie on this kind of install process :cry:

I think that should work everywhere but on osx - I'm not sure how you would write it for OSX

Maybe something on the top like 

```sh
if type 'ldconfig' > /dev/null; && $(ldconfig -p | grep cairo)? -eq 1 then
    exit 1
fi
```

(Untested)