* Won't read mixed case character constants like #\SpAcE.

* literal object create shallow-copies of themselves rather when used
	rather than returning a reference to a literal object.  This would
	be easier to fix if we were to fix the next `bug'.

* Builtin Collection classes cannot be subclassed!  Maybe this isn't
	technically an error, but it is certainly disconcerting.

* The following doesn't work because we don't handle the case of
	inherited and keyword specifications in class definitions
	correctly (yet).  Thus the following doesn't work:

     define class <bar> (<object>)
         slot bar-x, init-keyword: x:;
         slot bar-y, init-keyword: y:;
     end class <bar>;

     define class <baz> (<bar>)
         required keyword x:;
         keyword y:, init-value: #t;
     end class <baz>;

* Doesn't correctly identify bogus keywords because it checks only the
current method's keyword list rather than all applicable methods.
