[html-formfu] default_values

[Carl Franks]

The form object now has a default_values() method which accepts a
hash-ref of names/values, and uses them to set the fields default
values.

This should replace the idiom previously suggested on the list.

This should be called /after/ adding the fields to the form (if you
use a config file, then  populate() automatically takes care of it).

I'm currently in the process of cleaning up the FAQ and Cookbook
(there doesn't seem to be a clear distinction between the two) - I'll
remove the idiom from the docs, but it probably won't be committed
until tomorrow.

Cheers,
Carl