When checking whether to build a new revision, also update the rules working copy, use it's revision too when comparing the current revision with the already built revisions and use it when building a new revision. Update the tests for this. Part of this change is that now, the default revision for the rules is 0 not 1 as previously. To avoid extra builds, existing treepkg instances will have to be updated so that the directories end in -0 not -1. There will be a tool to help with this.