Required installer modules installed automatically on NSLU2 now

One thing that's annoying about the Debian installer on the NSLU2, as Joey Hess pointed out a few months ago when he reinstalled his NSLU2, is that you have to manually select some installer modules. The reason for this is that the NSLU2 only has 32 MB of RAM and thus Debian installer runs in lowmem mode in which less functionality is enabled by default. As a result of this, you have to select partman-auto, partman-ext3 and usb-storage-modules from a list of additional installer modules to load so the installer will recognize your USB disk, offer guided partitioning and format the disk with ext3.

When Joey submitted his installation report, Frans Pop suggested that we could put a list of installer modules we want to have installed automatically in /var/cache/anna/include. I finally got around to playing around with this yesterday and while this specific solution won't work on lowmem systems we can use anna-install to automatically queue installer modules for installation. Since anna-install works, I put some functionality into the installer today to automatically load required installer modules on the Linksys NSLU2 and on Cobalt machines.

This change is good for users because they don't have to select some modules during the installation. I'm a little bit worried that existing users of the installer on the NSLU2 will be confused when they don't see the modules in the list anymore, but I'll update the documentation accordingly.