Documentation of links to be improved

[prjemian]

The documentation of links in data files can be improved.

On 2/12/2015 10:39 AM, Andrew GOETZ wrote:

A second question we had is that the way the application definitions are
defined today implies they duplicate data in the file instead of linking
to it. This is because they insist on creating NXsubentry. Please
correct me if we have misunderstood the use of NXsubentry.

"Implies" -- the whole process needs some documentation that describes how links can be used to reduce duplication (and size) in NeXus data files.

Enrich the documentation of links and then add some text at the beginning of the NXDL application definitions chapter to state that links can (and probably should) be used whenever possible to reduce duplication.

[prjemian]

This issue is about when to use NXsubentry as much as it is about NeXus links. See #582.

Completion of the suggestion to promote the recommendation of links will satisfy this issue.