typo fixed and simplify code for read the data values arguments of formula functions

* Fix build-in scientific number format failed
* An error will be returned if given an invalid custom number format when creating a new style

- Rename exported field `File.XLSX` to `File.Pkg`
- Exported error message

typo fixed

* extend cell value load to support custom datetime format

* cleanup incorrect imports

* fix numeric values conversion as done in legacy Excel

* fix tests coverage

* revert temporary package name fix

* remove personal info from test XLSX files

* remove unused dependencies

* update format conversion in parseTime

* new UT to increase code coverage

* Resolve code review issue for PR #703

* Rename broken file name generated by unit test
Co-authored-by: xuri <xuri.me@gmail.com>

- styles: allow empty and default cell formats, #628

Closes #390

add error return value

exported functions:

GetMergeCells
ProtectSheet
UnprotectSheet
UpdateLinkedValue
GetMergeCells
SetSheetVisible

inner functions:

workSheetReader
copySheet