Add tile log analysis

This adds a process which runs a cron job processing the tile logs into summaries of "z/x/y count" daily.
I usually use root rather than the user it is going to run as when checking out and building code, so that the results are not writable by the actual jobs which do the work.

Downside is building as root which is't good, upside is protecting the code from being changed during runs. Maybe we should really have a separte use for this...