Drop vg dependency

We only use one function from vg so I dropped that to clean up a little bit the dependencies. The main reason for this was due to the fact that vg is not on released on Conda and we need to create a Conda package to make things easier. The introduction of the new M1 Apple CPU made installing Python packages pretty horrible and Conda is currently the only way to get the correct dependencies. pip cannot even install numpy 🙈