looping on rows columns functionality

Update README.md @schigh 👌 Thanks for your pr.

added missing imports

Revert "Update README.md"

Update README.md @schigh Thanks for u pull request.

Adding more realistic error handling in examples

Make readme highlight code

Open file error return added and UpdateLinkedValue function added to fix linked values within a spreadsheet are not updating.

1) Update readme file credits and go report badge added; 2) Remove use less function; 3) Update test file.

- Optimisation code use fmt package
- Update README
- Remove useless function