Definition of "container element" in SVG 1.1

I don’t think the set of elements in the “container element” definition
in SVG 1.1 is right.  It currently says:

  An element which can have graphics elements and other container
  elements as child elements. Specifically: 'svg', 'g', 'defs'
  'symbol', 'clipPath', 'mask', 'pattern', 'marker', 'a' and 'switch'.

First, <clipPath> cannot contain just any graphics or container element;
it only allows basic shapes, <path>, <text> and <use>.  So I think it
should be removed.

Second, both <glyph> and <missingGlyph> have the same content model as
<g>, so I think they should be added.

-- 
Cameron McCormack ≝ http://mcc.id.au/