* list.[ch] (scm_i_finite_list_copy): New internal function to

	* list.[ch] (scm_i_finite_list_copy): New internal function to
	copy lists that are known to be finite (though not necessarily
	proper).

	* debug.c (scm_procedure_source): Don't have scm_unmemocopy treat
	a closure's argument list like an expression of a body.

	* eval.c (unmemoize_expression, unmemoize_exprs, unmemoize_and,
	unmemoize_begin, unmemoize_case, unmemoize_cond, unmemoize_delay,
	unmemoize_do, unmemoize_if, unmemoize_lambda, unmemoize_let,
	unmemoize_letrec, unmemoize_letstar, unmemoize_or,
	unmemoize_set_x, unmemoize_apply, unmemoize_atcall_cc,
	unmemoize_at_call_with_values, unmemoize_future, sym_atslot_ref,
	unmemoize_atslot_ref, sym_atslot_set_x, unmemoize_atslot_set_x,
	unmemoize_builtin_macro): New static functions and symbols.

	(scm_unmemocopy): Rewritten in terms of the above.  scm_unmemocopy
	now has a slightly different meaning: The memoized form that is
	receives as its argument is now interpreted as a sequence of
	expressions from a body.

	(unmemocar, scm_unmemocar): Since the whole functionality of
	unmemocar and scm_unmemocar is not needed any more, scm_unmemocar
	has its old content back and is deprecated, while unmemocar has
	been removed.

	(SCM_BIT7): Removed.

	(CEVAL): For unmemoizing a single expression, call
	unmemoize_expression instead of scm_unmemocopy, which now expects
	a sequence of body expressions.  Eliminated unnecessary empty
	environment frame when executing let* forms.  Eliminated
	unmemoization step from evaluator.