Rev0 - add dropdown and updated to use now rev aware balanced.json

The current docs are building off a old balanced.json file, there is a fix for that in this pull request to use the new balanced.json file that supports revisions.

This also adds a dropdown to select between revisions, but rev1 is not ready yet as we can not yet hit the api to generate the json results of the requests.  The work for rev1 is being done in the rev1 branch.

We might want to disable the revision selector drop down atm as rev1 is not ready.