* print-gensym now accepts the symbol "pretty" as a valid
argument.
* The writer prints #:pretty-name if the print-gensym value
is |pretty|.
* The reader accepts #:id as a valid syntax. The result is
a fresh gensym with id as a pretty-name.
#{id0} => a fresh gensym with pretty-string id0
#{id0 id1} => an interned gensym with pretty-string id0
and unique-string id1.
id0 and id1 can have any identifier syntax including bar-quoted ids.
any number of whitespaces can be placed around id0 and id1.
Abdulaziz Ghuloum