docs changes

[Havoc Pennington <hp redhat com>]

Hi,

As discussed a really long time ago, I moved Changes-*.txt into the
reference manual, and also README.linux-fb. There's still an empty
win32 section in the reference manual it would be nice to get some
info in, at least a link to the win32 home page.

I also added a "How do I...?" index to the ref manual, it only has 5
or so questions so far though. This index should never contain
substantial docs/examples, it should just link to other parts of the
manual.

Havoc