Added examples for R API
Added examples for R API

ibtawfik/spark-csv,yl2695/spark-csv,databricks/spark-csv,abridgett/spark-csv,methodmill/spark-csv,YanjieGao/spark-csv,codeaudit/spark-csv,nvoron23/spark-csv,sunilyadavsky/spark-csv,sunilyadavsky/spark-csv,mohitjaggi/spark-csv,yl2695/spark-csv,abridgett/spark-csv,gasparms/spark-csv,YanjieGao/spark-csv,akirakw/spark-csv,XiaoqingWang/spark-csv,gilv/spark-csv,codeaudit/spark-csv,gasparms/spark-csv,saurfang/spark-csv,saurfang/spark-csv,gilv/spark-csv,gasparms/spark-csv,karenyyng/spark-csv,andrewrothstein/spark-csv,methodmill/spark-csv,falaki/spark-csv,andrewrothstein/spark-csv,sunilyadavsky/spark-csv,abridgett/spark-csv,XiaoqingWang/spark-csv,YanjieGao/spark-csv,gilv/spark-csv,databricks/spark-csv,karenyyng/spark-csv,falaki/spark-csv,akirakw/spark-csv,databricks/spark-csv,nvoron23/spark-csv,ibtawfik/spark-csv,falaki/spark-csv,mohitjaggi/spark-csv