This code updates the cell_measure records. But it doesn't trigger anything to use these new complete records to update the cell table and get a better position estimate for the real cell. The `ichnaea.tasks.cell_location_update` currently does the location update of the cell table, but it's based on taking the last X new records. In this case we'll have a number of older records to consider.

So we need a new task or refactor the cell_location_update task to take a list of cell_measure ids to work on. The new task should get a list of new cell_measure ids, calculate the new cell location and update the cell.total_measures column to keep track on how many data records the estimate is based on.