* 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>

-  added 3 internal function: getSheetID, getActiveSheetID, getSheetNameByID

Resolve #580, revert commit https://github.com/360EntSecGroup-Skylar/excelize/commit/5ca7231ed408ac264f509ff52b5d28ff4fbda757

* Added accessors for Getting/Setting Page Margins

* Added test cases

SheetID only seems to indicate the file name for the sheet.
Check the sheets list based on index instead. Reordering sheets
in Excel changes the order they appear in that list.

Fixes #457