* The list of candidates now includes unknown variants. When an unknown
variant is selected, the unknown game dialog is shown.
* On the unknown game dialog, users are given the choice to add the game
when that is possible, or to cancel.
The goal of those changes is to make the unknown game dialog less
confusing for users, especially when both known and unknown games
variants are found.
The redirect rule on the web site expected only two query items, one
with the engine name and another one with the description. However it
was a bit lax in its regex and we could pass additional query items
as part of either the engine name or description. The unknown game
dialog was abusing it to pass a summary.
The rewrite rule for the URL on the web site has now been fixed to
avoid such abuse. And instead it also adds a summary. So the
unknown name dialog should no longer provide one.
The code is still disabled, but it is now in a working state and
can be tested by removing the #if 0 and changing the URL to a test
server with a redirect rule.
This should also fix this for other instances of ScrollContainer, though
the dialogs / widgets may require the same change.
This fixes bug Trac #10741.
