Deal with .generation double-sided support for CUPS

[jdreed]

According to Mark Manley, creating ~/.cups/lpoptions which contains

Options sides two-sided-long-edge

should work. So the dotfiles should be changed to do this for accounts with .generation >= 1. Evan notes that we should do something clever to ensure that it goes away if a user removes .generation.

[broder]

I may be doing something wrong, but I wasn't able to get that to work from Debathena Jaunty (specifically, from kid-icarus), and I don't see anything to suggest that ~/.cups/lpoptions supports that syntax in the source either, although I could have been missing something.

[jdreed]

We're going to move ahead with making the cluster printers default to double-sided, and providing instructions to override that when simplex is required. Testing is REQUIRED to verify that simplex overrides are possible from OO.o, Evince (or other Gtk app), Acrobat Reader, and the command line.

We have tenatively picked Spring Break as a good time to flip the duplex switch, as that coordinates with mmanley's vacation.