[Nexus] NeXus version

[Pete Jemian]

Jan:

Thanks for launching the discussion on this "buried" problem.

On 1/23/2015 7:58 AM, Jan Kotanski wrote:
> Ah, so NeXus format is defined by application definitions and base
> classes are only helpers.

base_classes should be considered as blocks for organization

> Indeed, in that context the NeXus_version attribute does not make sense.

At least for now, that is a fair conclusion.  As stated before, the use 
of this attribute is dated to the time when all NeXus files were written 
through the NAPI.  Today, that is not always the case.  The 3.1.0 
version number in the definitions repository is not the best value to 
use either.

A better explanation requires more time.  I'm in an all-day hands-on 
training class.  We should take this (overall version number) on as a 
GitHub issue in the definitions repo for consideration.

Pete