PR featuring configuration, optional impersonation support, and optional last login support

Hi,

I meant to do this before, but got a bit distracted, but I needed last login support today, so I figured I try and do it in a useful way for the main branch.  I added a general configuration facility, but made it optional so I thought that would be more in the spirit of what library's general feel is.  Anyway, happy to hear feedback if you don't like the approach.  

cheers,
andy