Infer index.htm[l] for missing file names

Seen this as a pending feature in the readme.

Two ways to do it:

1. This line in the .htacess will append 'index.html':
#RedirectMatch (.*)/$ $1/index.html

Downside is that this alters URLs. Pages that were previously accessed at /foo/bar/ now show as /foo/bar/index.html in the browser.

2. in get_page() in class_wghtml.php, line 76, add a test to see if $_SERVER['REQUEST_URI'] ends with / and if so, append index.html.
Advantages is that this is transparent to the user.