Recreating the Flex 3 LinkBar and LinkButton in Flex 4

Recently I needed a proper Flex 4 version of the venerable Flex 4 LinkBar (a horizontal line of links), but all I could find was a posting of the beginning of the implementation. I also needed it to behave as a toggle so any one link could be selected.
Flex 4 doesn't have a LinkButton either, so I had to make one of those too.
Both components then needed a suitable skin.

So, four files :-) Fairly easy once I got going with it, and you can see the (very exciting) example attached below, along with the source code.