[development] .htaccess patch for 404 of Non-drupal files

[Peter Wolanin]

In regard to this:

> Khalid B wrote:
> > It is worth including the change in this page http://drupal.org/node/56773
> > to the standard .htaccess we distribute?
> >

I think it's good change, but I'd suggest also adding the extentsion .htm