Reducible streams do not implement clojure.lang.Sequential

[glts]

This change makes reducible streams implement clojure.lang.Sequential.

The reducible and seqable value returned by decode! does not implement clojure.lang.Sequential, even though it is sequential. I believe it is common and beneficial for such values to implement that marker interface, as it enables some interopability with consumers that rely on that marker (eg sequence specs).

Example: this program prints false now, true with the change applied.

echo 1 2 3 | clj -e "(use 'pjstadig.reducible-stream) (= [1 2 3] (decode-edn! *in*))"

Thank you.