[Vimperator] walk input fields

[Takayama Fumihiko]

Hi,

I wrote a plugin which moved the focus along the input fields.
When the web page has multiple <input> or <textarea> fields,
the focus walks the input fields by pressing A-i (or M-i).

http://www.pqrs.org/tekezo/tmp/vimperator/walk-input.js

It seems there was no similar function in the core code, would you merge this?

Regards,
Takayama Fumihiko.