Create an ability to pre-calculate simple queries

Basic functionality is just aggregates with no filters and group_by's.
Aggregation manager is a 'periodic task' that will call 'aggregate' method every hour and every day.
Example of aggregate for HBase:
 image_9223372035472681807 column=H:avg, timestamp=1389255460712, value=1.0
 image_9223372035472681807 column=H:count, timestamp=1389255460712, value=1
 image_9223372035472681807 column=H:max, timestamp=1389255460712, value=1
 image_9223372035472681807 column=H:min, timestamp=1389255460712, value=1
 image_9223372035472681807 column=H:sum, timestamp=1389255460712, value=1
 image_9223372035472681807 column=H:unit, timestamp=1389255460712, value=image