[tei-council] better constraints

[Syd Bauman]

There are a few elements in the TEI scheme which should, I think,
have their *content* constrained to an appropriate datatype. In
paricular: 

  element        current declaration      should be
  -------        ------- -----------      ------ --
  <gi>           text                     data.name
  <att>          text                     data.name
  <altIdent>     macro.xtext              data.name

Any objections?