GiST concurrency

Wow. This was pretty fast. On top of the WAL fixes, GiST concurrency fixes are now in, courtesy of Teodor and Oleg (and possibly others? Those are just the ones I know of..) With time to spare before 8.1. Great job guys!

I know at least one of my projects where this feature alone will make me upgrade to 8.1 the day it is released.