On-site analytics update

Just pushed a much needed tracking update for sub-user accounts, so now they can use on-site analytics, and their traffic will now also be automatically ignored.

Previously this was not possible because of the way our tracking servers were caching information about each site in memcached. After banging heads on keyboards for a while, we finally figured out a way to do it (it's more complicated than it sounds). So, now sub-users will have their traffic ignored automatically, and they will see the on-site analytics widget.

One caveat - the master account's preference for disabling on-site analytics on an account wide basis will override a sub-user's preference.

Making this change also addresses a bug that popped up after the four-week heatmap trial ended a few days ago. All sub-user accounts are created as "Pro", since Pro has always had access to every feature, and a Pro account was required to have sub-user accounts. But now that heatmaps require Pro Plus or higher, heatmap tracking broke for some of you if you had created another sub-user account and assigned them admin access to a site in your account. Their account features were overriding yours on the tracking servers for the sites they had admin access to. So this update fixes that. But we went ahead anyways and made sub-users account types mirror the master accounts - any time the master account type changes, the sub-users are updated accordingly, to address any future updates that might cause this scenario to come up again.