Code the function, removeNILTop, which is passed a list and removes NIL at the top level.

Examples:

> (removeNILTop '(NIL X NIL NIL Y NIL Z))

(X Y Z)

> (removeNILTop '(X NIL Y NIL Z NIL))

(X Y Z)

> (removeNILTop '(NIL (X NIL Y) (NIL NIL)))

((X NIL Y) (NIL NIL))