Start of first metric reducer
Added getProperty method to Aggregations

This allows arbitrary properties to be retrieved from an aggregation tree
Delta reducer working

Need to tidy it up a bit but it works. On of the first things to tidy up will be the fact that nested reducers since require the "buckets" field in the parser even though they are not used in the reducer itself. For now you can put any value in this field since its ignored
draft for lin regression
use getProperty method and switch to apache commons math