Indicate which architectures are in universal ports?

[Ryan Schmidt]

In "port installed" I can see which ports I have installed universal  
and which I haven't. But for those that are universal, I can't see  
what architectures are represented (since we now allow people to  
change that via the macports.conf). This makes it hard if, e.g., I've  
decided that I want to upgrade from having 2-arch universal builds to  
having 4-arch universal builds. Maybe "port installed" could be  
enhanced to show which architectures a port was built with? This  
could apply only to ports with the universal variant, or maybe better  
to all ports. Comments? Other ideas for solving this problem?