investigate use of realtime gc as the recommened default for server vm

We currently don't recommend that ppl use the realtime gc when running the server, we probably should.

Before we do so we need to verify that it works.
We should make it the default for all our tests.
concurrent vs "g2" or whatever it's called (new in 1.6_15 or something?)
Update all scripts to specify this option
update documentation to include this option and add section in the dev/ops docs detailing it's benefits (in particular latency effects of gc)

Also, -server option? any benefit for us to recommend this as well?