Arima/initial

Initial implementation of ARIMA Time Series support, and a few helper BLAS and related attributes.
Is this correct? sort(file,x,y) can result in a single 'x' spanning nodes ... did you really want
DEDUP( SORT( DISTRIBUTE(model_id), model_id,period,local), model_id, RIGHT, local) ???

if there are too few model_ids for that you MAY need to do what you are doing, THEN distribute by model_id and dedup again