ignores authentication, proxy config from settings.xml

[jdcasey]

Eventually we may need to process server and proxy sections of the settings.xml and apply them to the locations created in MavenLocationExpander.

If they're already applied to the ArtifactRepository instances passed to the location expander (definitely possible), then we need to read that config from the repo instances and translate them to the Location instances we create.

This is relatively low priority, esp. compared to mirror usage.