convert S4 to S3; add some extra methods to DMatrix

R-package/man/print.xgb.DMatrix.Rd

@@ -0,0 +1,18 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/xgb.DMatrix.R
+\name{print.xgb.DMatrix}
+\alias{print.xgb.DMatrix}
+\title{Print xgb.DMatrix}
+\usage{
+print.xgb.DMatrix(x, verbose = FALSE, ...)
+}
+\arguments{
+\item{x}{an xgb.DMatrix object}
+
+\item{verbose}{whether to print colnames (when present)}
+}
+\description{
+Print information about an xgb.DMatrix. 
+Currently is would display
+}
+