excelOutput             Helper function for using jexcel table in Shiny
excelTable              Create excel table using jexcel library
excel_to_R              Convert excel object to data.frame
getComments             This function is used to get comment from
                        specified cell
get_selected_data       Get selected cells from excel table
get_selected_data_boundary
                        Get selected cells boundary from excel table
renderExcel             Helper function for using jexcel table in Shiny
setComments             Add comment to a specified cell
