[tei-council] conforming binary objects

[Syd Bauman]

This is not immediately germane to the conformance discussion, but I
thought I'd mention it now, primarily for Matt Z. and James C., lest
it be forgotten.

A component of P3 & P4 conformance is that there be no binary data
other than in declared notations:
    
  * [a TEI-conformant document] contains no non-SGML, non-XML markup
    other than declared notations for graphics, tables, figures, etc.
    That is, unless a declared notation is in use, the semantics of
    any content character in the document are exhausted by its
    identity as a graphic character.

This needs to be re-written to account for the fact that the
mimeType= attribute of <binaryObject> is not a declaration.