Feature request: Optional custom proxy settings

[igitur]

Hi,

I would like to optionally override the system proxy settings with custom proxy settings. Very similar to how Firefox's proxy settings dialog box is.

This would be useful in our corporate environment, where our default proxy uses NTLM auth and that sometimes causes issues. I have a local CNTLM proxy to handle the auth, and would like to force NPackd to use the local proxy without having to adjust my system proxy settings.