write_sheet: Write single object to a MS Excel File
In carleshf/loadxls: Easy reading and writing MS Excel files from R

Given a single data.frame, it saves it as sheet in a MS Excel File.

1 2	write_sheet(data, sheetname, filename, include.rownames = FALSE, replace = FALSE, verbose = TRUE)

`data`	`data.frame` to be saved as sheet in a MS Excel File.
`sheetname`	Name to be given to the sheet.
`filename`	The path and the name to the MS Excel File.
`include.rownames`	If set to `TRUE` adds the `data.frame`'s rownames as a new column in the sheet.
`replace`	If set to `TRUE` it replaces the content of the given sheet with the current value of `data`.
`verbose`	If set to `TRUE` usefull messages are shown.