Update implementation links to add Andreas' wireshark plugin and re-organize.

The previous organization inappropriately made it seem like some implementations weren't ready for production even though they are actually being used in large-scale production already. The problem is that these projects haven't actually implemented 100% of the spec, but they have no need to, because what they have is good enough for their purposes, so their categorization was unlikely to change. I've now simply classified implementations as "Serialization + RPC" vs. "Serialization only", which seems like the most that can be said without getting subjective and ambiguous.
Add David's new Java implementation to web site.