list tool support on front page

[rsc]

What tools understand vendor.json and can be expected to work with it? I don't actually know. I saw reference to Daniel's govendor earlier, which was the first I'd heard of it. I think maybe nut supports vendor.json. I thought godep did but now it looks like maybe it just supports the vendor/ directory tree, not vendor.json itself. Some clarity on what tools to use to try "vendor.json" out would help. Maybe it would encourage others to update their own tools to use it too.