StringObservable.split NPE fixes

[davidmoten]

check for null values of leftOver in onCompleted and onError.

Added two failing unit tests that passed with fix.

@benjchristensen I suppose should I make PR on RxJavaString as well?

[cloudbees-pull-request-builder]

ReactiveX » RxJava » RxJava-pull-requests #17 SUCCESS
This pull request looks good

[benjchristensen]

Yes, it will also need to be done against RxJavaString

[davidmoten]

@benchristensen This change was documented as in 0.20.4 release of rxjava-string but did not make it somehow. The 0.20.x branch contains the change. Can you update the documentation of 0.20.4 release to exclude this PR and add it to your list for 0.20.5 when/if ever that happens?

[benjchristensen]

It was merged on September 4th into the 0.20.x branch. The 0.20.x branch was then released and tagged as 0.20.4 on September 5th.

You can see the commits and tags here: http://github.com/ReactiveX/RxJava/commits/0.20.x

How would 0.20.4 not contain the change when the build, release and tag happened a day after this pull request was merged?

[davidmoten]

My mistake Ben. Eclipse was showing old source code with the 0.20.4 dep, I'll sort it out. I went to maven central and downloaded the sources jar and checked it and all good. I should have done that check before posting. Cheers.