hxl2*: common issues and/or opinionated decisions on for all HXL D.S. exporters

[fititnt]

hxl +public
meta +status	working-draft
meta +id	EticaAI-Data_HXL-Data-Science-file-formats_hxl2
meta +discussion+public	#5
meta +hxlproxy +url	https://proxy.hxlstandard.org/data?dest=data_view&url=https%3A%2F%2Fdocs.google.com%2Fspreadsheets%2Fd%2F1vFkBSharAEg5g5K2u_iDLCBvpWWPqpzC1hcL6QpFNZY%2Fedit%23gid%3D1797514580
meta +description	This dataset contains general ideas of common issues or recommendations thatare expected to affect all HXL2 exports (code: hxl2) or some specific exporter(like hxl2tab for Orange Data Mining or hxl2arff for Weka).This does not mean that all issues here are already solved on eachimplementation, but at least is a place for reference.

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This issue is just a common place to comment or reference on commits points that are very likely to affect all (or at least most) data science file exported based on this project.

TODO: update with more information done.