Add Methods To Delete and Replace Worksheets

[notrexhere]

I have gone over the readme and the samples and I can't determine if the following two actions are possible or not:

1. Open an existing workbook, delete a worksheet and save it back.
2. Open an existing workbook, replace a worksheet with all new content, cell data wise, leaving any formatting and styling in tact as much as possible.

I would like to see these use cases added to the test section.
Thank you!