Groups the tiles when getting them from database.
Groups the tiles when getting them from database.

When trying to get the stations from cache, if they fail, we group the
tiles we have to query in the DB (at the moment it works only on one
direction, from west to east). This reduces signifincantly the number
of queries.
SeGarVi/moveon-web,SeGarVi/moveon-web,SeGarVi/moveon-web