unquote splicing and implemented slime side list comprehensions

bin/tests/lexical_scope.slime.expanded

@@ -1,4 +1,4 @@
-(define (make-counter) (let ((var 0)) (lambda () (mutate var (+ 1 var)) var)))
+(define (make-counter) ((lambda (var) (lambda () (mutate var (+ 1 var)) var)) 0))
 
 (define counter1 (make-counter))