cast longs to doubles in scala for correct NAs and fix #463
cast longs to doubles in scala for correct NAs and fix #463

kevinykuo/sparklyr,rstudio/sparklyr,kevinykuo/sparklyr,kevinykuo/sparklyr,rstudio/sparklyr,kevinykuo/sparklyr,rstudio/sparklyr,rstudio/sparklyr