update NAMESPACE

NAMESPACE

@@ -135,6 +135,7 @@ importFrom(ggplot2,element_blank)
 importFrom(ggplot2,facet_wrap)
 importFrom(ggplot2,geom_abline)
 importFrom(ggplot2,geom_density)
+importFrom(ggplot2,geom_histogram)
 importFrom(ggplot2,geom_point)
 importFrom(ggplot2,ggplot)
 importFrom(ggplot2,ggsave)
@@ -146,6 +147,8 @@ importFrom(ggplot2,sym)
 importFrom(ggplot2,theme)
 importFrom(ggplot2,theme_bw)
 importFrom(ggplot2,unit)
+importFrom(ggplot2,xlab)
+importFrom(ggplot2,ylab)
 importFrom(gridExtra,arrangeGrob)
 importFrom(gridExtra,grid.arrange)
 importFrom(gridExtra,tableGrob)