[XML-SIG] Recipe DTD revision

[Andrew M. Kuchling]

I've made some changes to the proposed recipe DTD.  The two most
important open issues are metadata -- I'm still reading the RDF spec
-- and how to represent a range as an amount, such as "2 - 3 cups".
Once those issues are resolved, I'll feel confident enough to actually
start writing code that uses the DTD.

List of changes:

	* Renamed the 'note' to 'comment', and added a class
attribute, so you can have <comment class="tip">, <comment
class="variation">, or whatever.

	* Added 'optional' and 'precision' attributes to ingredient
element.  'optional' has a yes/no value, and 'precision' is either
'exact' or 'approximate'.

	* Added 'id' attributes to recipe, ingredient, alt-ingredient,
group, and comment elements, that all have the ID type, and are
intended to allow referring to a specific element.  

	* I'm not going to bother lowercasing the element names in 
the IBTWSH DTD, which is used to provide HTML-like elements for 
textual content.

	While it's inconsistent to have the recipe elements all be
lowercase, and the HTML elements uppercase, documents will almost
certainly be generated by software.  I've tried entering a recipe by
hand, and found the most annoying part is entering the list of
ingredients, because it's so mark-up heavy.  You really, really want a
GUI to do this for you, and that would also hide this inconsistency.

-- 
A.M. Kuchling			http://starship.python.net/crew/amk/
Well, there are these two people here, Sir. The man says he drank wine with
you somewhere called Babylon, and the lady... she's making little frogs.
    -- The receptionist, in SANDMAN #43: "Brief Lives:3"