Strings.split appends extraneous empty strings

```
// java String.split() works as expected
assertEquals(1, "Hello World\n".split("\n").length);

TestSubscriber subscriber = Strings
.from(new StringReader("Hello World\n"))
.compose(Strings.split("\n"))
.test();

subscriber.assertValueCount(1); // Fails with a result of '2'
subscriber.assertValues("Hello World"); // Fails with a result of ['Hello World', '']
```