readActiwatchCount for csv data assumes English PC languages

[vincentvanhees]

It appears that Actiwatch .csv file format can be in local language of the user.
For example, the "marker" column is saved as "markering" in The Netherlands, this is problematic as it will complicates retrieving marker button data based on column name across languages.

Possible solutions:

1. Account for each translation of marker button and possibly other column names in Actiwatch data? => Large amount of work, although on an ad-hoc basis I could add some auto-translations for some languages.
2. Recommend exporting data to English? => At least highlight in the documentation that most functionality was tested in English.
3. Provide guidance on which column names are critical to be in English for GGIRread/GGIR such that user can change them if re-exporting is not an option => Not ideal to have user fiddle with their data.