Change the builder so that the version sync code is on the server.

This will make builds much faster, and reduce a lot of overhead around HTTP calls. It should keep the versions in the repo and the versions on the server properly in sync. This has been a long standing bug where people have changed tags and we wouldn't update the code on checkout correctly.
Exclude active versions from deletion too.
Merge pull request #415 from rtfd/server-version-sync

Change the builder so that the version sync code is on the server.