Using a custom command is awkward

In the case of [robotlab](https://github.com/bollwyvl/robotlab/pull/8/files#diff-15f42e80720b823bbc12d1ad8ae9990fR10), which doesn't call `jupyter notebook`, it's pretty awkward to hand off the arguments. Should figure out something a little more elegant. Simplest fix might be `jupyter-notebook`.