[html-formfu] nested params merged

[Carl Franks]

I've merged the nested-params branch back into trunk.

Although there's extensive new tests, I haven't tried it out with a
real application yet - so there may be some teething issues.
Documentation's still needing done.

Some of the template files have been changed - as they need to use
'nested_name' now rather than 'name'. (The next thing I'm going to
work on will make it easier to use templates and easier to upgrade
HTML::FormFu).

To expand on the examples in my last mail...

You can set a Form or Block elements nested_name().
You still just set name() on fields.

$field->nested_name() returns the full name that'll be used in the form markup.

If you set $form->nested_subscript(1), elements names will have the
form "foo[bar][baz]" instead of "foo.bar.baz"

If a field-name or intermediary nested name is an integer, the data
structure returned by $form->params() or $form->param() will be an
array-ref:

"foo.bar.0" => 1
"foo.bar.1" => 2

If you're using any of the Callback processors, or have written your
own processors (constraints, validators, etc) - they generally get the
relevant input value as their 1st argument, and the $params hash-ref
as their 2nd argument.
Because the $params hash-ref is no longer a single-depth hash, but may
contain nested structures, you should no longer simply do stuff like
this:
    $foo = $params->{foo};
    $params->{foo} = $foo;
    if ( exists $params->{foo} ) { }

You should instead use the following helper methods:

    $foo = $self->get_nested_hash_value(
        $params, $nested_name );

    $self->set_nested_hash_value(
        $params, $nested_name, $value );

    if ( $self->nested_hash_key_exists(
        $params, $nested_name ) )
    { }

Um, that's all I can think of for now...

Carl