Add error page; remove index.php from urls

I finally got the .htaccess file working such that routes now work as
local.wefinance.co/faq and so on.
This may require a change to your apache config (if by default it
doesn’t allow .htaccess files to do anything; you may have already
dealt with this).

Also added a catchall error page which seems to properly catch all
unassigned routes.  Something like /permalink/garbage does get you to
the error page, but /permalink/ on its own doesn’t get you to an error
(presumably because it still has a route) and anything invalid with
/permalink/? and thing garbage also doesn’t get you to the error page.