panels 5.x-2.0-alpha10

Arguments! Holy cow arguments are cool.

- Right now the scope of arguments you can add is really limited -- you get the Node argument (which works about as well as I can) and the taxonomy argument (which does not yet have any related content). I need to add the taxonomy content and actually implement the taxonomy argument context (what's there is just a placeholder), as well as the user context. Also this needs to be able to integrate with Views more naturally, so that a context can translate easily to a views argument. That's a bit of work.

- Each argument can create different displays. For node, it can do different displays based upon the type. For taxonomy it'll be able to do it based upon the vocabulary (though that's not there yet). And you can have a different display for the argument being not present.