Remove empty function and bump plyr dependency to 1.0

DESCRIPTION

@@ -6,7 +6,7 @@ Author: Hadley Wickham <h.wickham@gmail.com>
 Maintainer: Hadley Wickham <h.wickham@gmail.com>
 Description: An implementation of the grammar of graphics in R. It combines the advantages of both base and lattice graphics: conditioning and shared axes are handled automatically, and you can still build up a plot step by step from multiple data sources. It also implements a sophisticated multidimensional conditioning system and a consistent interface to map data to aesthetic attributes. See the ggplot2 website for more information, documentation and examples.
 Depends: R (>= 2.7)
-Imports: reshape (>= 0.8.0), plyr (>= 0.1.8), splines, MASS, RColorBrewer, grid, proto, digest
+Imports: reshape (>= 0.8.0), plyr (>= 1.0), splines, MASS, RColorBrewer, grid, proto, digest
 Suggests: quantreg, Hmisc, mapproj, maps, colorspace, hexbin, gpclib, maptools
 Extends: sp
 License: GPL

R/utilities.r

@@ -166,12 +166,3 @@ invert <- function(L) {
 "%inside%" <- function(x, interval) {
   x >= interval[1] & x <= interval[2]
 }
-
-# Check if a data frame is empty
-# Empty if it's null or it has 0 rows or columns
-# 
-# @arguments data frame to check
-# @keyword internal
-empty <- function(df) {
-  (is.null(df) || nrow(df) == 0 || ncol(df) == 0)
-}