Bug#543256: Make installing recommends optional

[Frans Pop <elendil@planet.nl>]

On Sunday 23 August 2009, Frans Pop wrote:
> I think that supporting this option is well within the normal scope of
> D-I, which is very much about flexibility where possible.

Ah, I wondered what had happened to this mail. I was in the middle of 
adding attachments and suddenly it was gone. Must have activated "send" 
somehow.

This (first) one is incomplete, please see the second version.

I retyped the mail from scratch; feel free to compare them for an 
impression of the quality of my short-term memory ;-)