Replace templating with Sprintf for cells
Reduce templating and sprintf calls in CellIndex
Remove templating for sheet end
Remove tests for old templates
Merge branch 'sean-duffy-string-formatting-changes'

* sean-duffy-string-formatting-changes:
  Remove tests for old templates
  Remove templating for sheet end
  Reduce templating and sprintf calls in CellIndex
  Replace templating with Sprintf for cells