Upgrade existing WPKG-GP with password

```
I'd like the installer to find the existing wpkg-gp.ini if it's already 
installed & read the network password from it. This was you can do a silent 
upgrade without having to manually provide the password. 




```

Original issue reported on code.google.com by `barry.ra...@tippingmar.com` on 7 Feb 2014 at 5:16
