Phoenix 180

First revision for review.  There are some open points here.  Still no test case added to consume the stats.  Will do the performance test once the system is available with me.
I'd rather just keep only what we need, especially for PTable. Keep the server-side code that figures out what the min and max are, but we won't need to calculate it for now.

I think once the guidepost work gets wrapped up, we can step back and do some design on what additional stats we'll need (to guide other optimization decisions) and how to surface these.