[Representation] proposal for identification of normative/non-normative parts

The proposal is to do the same as the SOAP Rec, ie:
Add in "Notational Conventions"
<<
With the exception of examples and sections explicitly marked as 
"Non-Normative", all parts of this specification are normative.
>>
And change the title of 2.3.3 to
"Extension example: HTTP resolver extension"

-- 
Yves Lafon - W3C
"Baroula que barouleras, au tiéu toujou t'entourneras."