[osis-core] header info format again

[Troy A. Griffitts]

> Did you not like the "dateFormat" attribute Harry suggested yesterday? ;-)
> 
> Not necessarily saying that we may not need "subtype" but would like to 
> know how it would differ from Harry's suggested usage of dataFormat.

Oh, no, that wasn't it, at all.  The "dataFormat" element is a nice 
global to have.  I guess my preface, below, did not adequately detach my 
statement from the current thread:

 > This may be a general suggestion, and may not specifically solve this 
 > problem, but it seems like we might have other cases where the global 
 > 'type' attribute does not suffice.


I was only suggesting that, since we already have a global 'type', we 
might consider extending it with a global 'subtype'.  If we do this, it 
might solve this problem, and others.