[css3-values] identifier type

The CSS3 Values spec defines a new type, the <identifier> type [1],
for user-defined identifiers.  These are specified as case *sensitive*
identifiers.  In specs where this notation is used, one has to know
that there's a distinction between the term "identifier" and the
"<identifier>" type.  I think this creates a certain amount of
confusion, I think it would be better to name this type '<user-ident>'
to avoid this confusion.

Regards,

John Daggett

[1] http://dev.w3.org/csswg/css3-values/#identifiers