[NTG-context] \date format according to ISO 8601

31 Jan 2011

      Hi,

in my opinion it makes sense to display the date in ISO 8601 format.

now:      \date  results in: January 31, 2011
ISO 8601: \date  would result in: 2011–01–31

In case Hans does not like this idea, is it possible to change it to make
ISO 8601 the default. Something like

\setupdate [format={year, –, mm, –, day}]

Regards
Marco