Sheet name case sensitivity

[wojciechczerniak]

Description

Extracted from #12

We should compare sheet names as case-insensitive and normalize them (to the one created with renameSheet or addSheet) on formula save as we do with other references.

• Normalize sheetName on formula save
• API methods getSheetID, removeSheet, doesSheetExist, isItPossibleToAddSheet, isItPossibleToRemoveSheet etc should be case-insensitive as well
• As @swistak35 mentioned in Worksheet reference #12 (comment) we have to propagate the change to unparser and any other internal use

Spec

I dodn't found special reference to sheet names. They are treated as any other reference.

[swistak35]

Done:

https://github.com/handsontable/hyperformula/blob/master/test/engine.spec.ts#L241-L249

https://github.com/handsontable/hyperformula/blob/master/test/cruds/adding-sheet.spec.ts#L71-L80

https://github.com/handsontable/hyperformula/blob/master/test/cruds/removing-sheet.spec.ts#L49-L56

https://github.com/handsontable/hyperformula/blob/master/test/parser/unparse.spec.ts#L300-L307

https://github.com/handsontable/hyperformula/blob/master/test/parser/parser.spec.ts#L365-L374