Multiviews: new names for English URLs

[Ineiev]

Hi,

Since new Multiviews-specific redirections are active
(and unlikely to be reverted), foo.html is not the name
for the English page any more (it is for the generic
localized version selected according to browser's settings);
the name for the English page is foo.en.html, so our lists
of translation links need regenerating, the sooner the better.

So the question is whether we want it to be configurable
or hardwired. WDYT?