[SPARK-16507][SPARKR] Add a CRAN checker, fix Rd aliases

## What changes were proposed in this pull request?

Add a check-cran.sh script that runs `R CMD check` as CRAN. Also fixes a number of issues pointed out by the check. These include
- Updating `DESCRIPTION` to be appropriate
- Adding a .Rbuildignore to ignore lintr, src-native, html that are non-standard files / dirs
- Adding aliases to all S4 methods in DataFrame, Column, GroupedData etc.  This is required as stated in https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Documenting-S4-classes-and-methods
- Other minor fixes

## How was this patch tested?

SparkR unit tests, running the above mentioned script

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes apache#14173 from shivaram/sparkr-cran-changes.

R/check-cran.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+set -o pipefail
+set -e
+
+FWDIR="$(cd `dirname $0`; pwd)"
+pushd $FWDIR > /dev/null
+
+if [ ! -z "$R_HOME" ]
+  then
+    R_SCRIPT_PATH="$R_HOME/bin"
+  else
+    # if system wide R_HOME is not found, then exit
+    if [ ! `command -v R` ]; then
+      echo "Cannot find 'R_HOME'. Please specify 'R_HOME' or make sure R is properly installed."
+      exit 1
+    fi
+    R_SCRIPT_PATH="$(dirname $(which R))"
+fi
+echo "USING R_HOME = $R_HOME"
+
+# Build the latest docs
+$FWDIR/create-docs.sh
+
+# Build a zip file containing the source package
+"$R_SCRIPT_PATH/"R CMD build $FWDIR/pkg
+
+# Run check as-cran.
+# TODO(shivaram): Remove the skip tests once we figure out the install mechanism
+
+VERSION=`grep Version $FWDIR/pkg/DESCRIPTION | awk '{print $NF}'`
+
+"$R_SCRIPT_PATH/"R CMD check --as-cran --no-tests SparkR_"$VERSION".tar.gz 
+
+popd > /dev/null

R/pkg/.Rbuildignore

@@ -0,0 +1,5 @@
+^.*\.Rproj$
+^\.Rproj\.user$
+^\.lintr$
+^src-native$
+^html$

R/pkg/DESCRIPTION

@@ -1,20 +1,18 @@
 Package: SparkR
 Type: Package
-Title: R frontend for Spark
+Title: R Frontend for Apache Spark
 Version: 2.0.0
-Date: 2013-09-09
+Date: 2016-07-07
 Author: The Apache Software Foundation
 Maintainer: Shivaram Venkataraman <shivaram@cs.berkeley.edu>
-Imports:
-    methods
 Depends:
     R (>= 3.0),
     methods,
 Suggests:
     testthat,
     e1071,
     survival
-Description: R frontend for Spark
+Description: The SparkR package provides an R frontend for Apache Spark.
 License: Apache License (== 2.0)
 Collate:
     'schema.R'

R/pkg/NAMESPACE

@@ -343,3 +343,12 @@ export("partitionBy",
 
 export("windowPartitionBy",
        "windowOrderBy")
+
+S3method(print, jobj)
+S3method(print, structField)
+S3method(print, structType)
+S3method(print, summary.GeneralizedLinearRegressionModel)
+S3method(structField, character)
+S3method(structField, jobj)
+S3method(structType, jobj)
+S3method(structType, structField)