Pylightxl

- bug-fix: occasionally a `<definedName>` tag would case pylightxl to add duplicate of the same worksheet, see issue [72](https://github.com/PydPiper/pylightxl/issues/75)
- update: updated date handling (code cleanup)
- added feature: added python2 compatible typing to the library
- added feature: added `io.StringIO` support to `readcsv`

- added feature: ability to update NamedRanges wb.update_nr(name, val), see issue https://github.com/PydPiper/pylightxl/issues/72
- added feature: ability to find where a NamedRange is wb.nr_loc(name)
- added feature: ability to fill a range with a single value: wb.ws('Sheet1').update_range(address='A1:B3', val=10)
- update: NamedRanges now add the worksheets if they are not already in the workbook. Note that using readxl with worksheet names specified will also ignore NamedRanges from being read in from the sheet that are not read in.
- update: updated quickstart docs with the new feature demo scripts

- bug fix: error in printing formulas that were read in as None type, see issue 59
- bug fix: added custom datetime and time style handling, see issue 36

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- improvement: added support for non-standard sheet ids, see issue [55](https://github.com/PydPiper/pylightxl/issues/55)
- improvement: added support for general IO file type inputs, see issue [57](https://github.com/PydPiper/pylightxl/issues/57)

- improvement: added support for non-standard sheet ids (created by 3rd party tools), see issue [53](https://github.com/PydPiper/pylightxl/issues/53)
- improvement: added support for writing to existing sheets that contain excel customization, see issue [54](https://github.com/PydPiper/pylightxl/issues/54)

- imporvement: added support for non-standard excel file xml tags, see issue `44 <https://github.com/PydPiper/pylightxl/issues/44>`_
- bug fix: fixed keyrow bug, see issue `47 <https://github.com/PydPiper/pylightxl/issues/47>`_
- bug fix: addressed csv writing issue related to cells that contain '\n' that previous started a new row. New version replaces '\n' with '', see issue `49 <https://github.com/PydPiper/pylightxl/issues/49>`_
- bug fix: newly written workbooks written by pylightxl could not create new worksheets within excel after opening. The fix was to removed sheetView xml tag, see issue `50 <https://github.com/PydPiper/pylightxl/issues/50>`_
- improvement: added encoding='utf-8' to write altworksheets to support chinese encoding error, see issue `51 <https://github.com/PydPiper/pylightxl/issues/51>`_