Launchers don't forward command line arguments to batch scripts

The `exe` launchers don't seem to forward command line arguments to the batch scripts. For example, 
```powershell
.\scripts\winjupyter_lab.bat "c:\"
```
opens JupyterLab with the notebook directory set as C:\\, but
```powershell
& '.\Jupyter Lab.exe' "c:\"
```
launches JupyterLab with the default notebook directory.