ROI.COM.AU’s latest changes (AdWords compatibility, plus other changes)

[chris-morgan]

Note that because we weren’t using all of the fields in the models at ROI.COM.AU certain changes which could have been made non-destructively (renaming fields) were instead made destructively (removing them), because I was lazy and we’re moving away from the caching-metrics approach where convenient (i.e. for new things). I explained it in the commit messages. There are also some changes you may disagree with or not want. Anyway, here it is, to merge or not, as desired.