[SPARK-2258 / 2266] Fix a few worker UI bugs

**SPARK-2258.** Worker UI displays zombie processes if the executor throws an exception before a process is launched. This is because we only inform the Worker of the change if the process is already launched, which in this case it isn't.

**SPARK-2266.** We expose "Some(app-id)" on the log page. This is fairly minor.

Author: Andrew Or <andrewor14@gmail.com>

Closes #1213 from andrewor14/fix-worker-ui and squashes the following commits:

c1223fe [Andrew Or] Fix worker UI bugs
[SPARK-2270] Kryo cannot serialize results returned by asJavaIterable

and thus groupBy/cogroup are broken in Java APIs when Kryo is used).

@pwendell this should be merged into 1.0.1.

Thanks @sorenmacbeth for reporting this & helping out with the fix.

Author: Reynold Xin <rxin@apache.org>

Closes #1206 from rxin/kryo-iterable-2270 and squashes the following commits:

09da0aa [Reynold Xin] Updated the comment.
009bf64 [Reynold Xin] [SPARK-2270] Kryo cannot serialize results returned by asJavaIterable (and thus groupBy/cogroup are broken in Java APIs when Kryo is used).