Make all of Lag private
Make all of Lag private

SeelozInc/spark-timeseries,cdalzell/spark-timeseries,sryza/spark-timeseries,samklr/spark-timeseries,sryza/spark-timeseries,cloudera/spark-timeseries,cdalzell/spark-timeseries,cloudera/spark-timeseries,SeelozInc/spark-timeseries