(Bug 4260) Redirect .htm to .html

Redirect .htm to .html, without dropping arguments,
with case insensitivity (as requested by Azz in
Bugzilla comments).
(Bug 5161) Switch styleid to siteviews instead of user's style

* we do this if the user has in their preference to use site skinned
  comment pages, rather than custom comment pages
* old way was to return to the caller telling the caller to use bml, and
  have the caller call LJ::S2::make_journal again. But siteviews is s2
  anyway, so we might as well set the right variables and continue on
Merge pull request #509 from afuna/bug5161-handle-siteviews-from-options

(Bug 5161) Switch styleid to siteviews instead of user's style