Single add forSingle and exceptionallyAccept

[danielkec]

Add terminal operation forEach equivalent to Single:

Single.just("test")
                .forSingle(s -> System.out.println(">>>" + s));
>>>test

Add exceptionallyAccept which takes consumer as parameter to CompletionAwaitable so there is no need to return something all the time, so instead of:

        Single.error(testException)
                .exceptionally(t -> {
                    t.printStackTrace();
                    return null;
                })

Is possible:

        Single.error(testException)
                .exceptionallyAccept(Throwable::printStackTrace);

Signed-off-by: Daniel Kec daniel.kec@oracle.com

[tomas-langer]

LGTM