[osis-core] header info format again

[Harry Plantinga]

> You are not using format in the sense of "rend" but in the sense of 
> "abbr" and "expan" (well, not exactly but you get the point) of TEI. 
> Hmmm, OK, that should be easy enough to add as an attribute value. 
> (Sorry it took so many tries for me to hear what you were saying!) I 
> assume it should be a datatype so that we can use the "x-" extension 
> mechanism for ones not defined in OSIS?

Right!

Wow, it really is hard to talk across disciplines, isn't it.  To a 
computer scientist, the _format_ of a piece of data has to do with 
how a _computer_ woudl read the data, not how it would appear to a
human...  XML is a format, ISO-9661 is a format, <i> is rendering...

> Perhaps an attribute "form"  that is documented to be a reference to 
> system (possibly outside the document for LC headings for example) that 
> govern the content. Sort of like the data typing of schema but without 
> the validation mechanism.

If format gives the wrong connotations to you, "form" seems a bit vague
to me, with irrelevant connotations.  How about dataFormat? scheme? 

-Harry