SPARK-1565, update examples to be used with spark-submit script.

Commit for initial feedback, basically I am curious if we should prompt user for providing args esp. when its mandatory. And can we skip if they are not ?

Also few other things that did not work like
`bin/spark-submit examples/target/scala-2.10/spark-examples-1.0.0-SNAPSHOT-hadoop1.0.4.jar --class org.apache.spark.examples.SparkALS --arg 100 500 10 5 2`

Not all the args get passed properly, may be I have messed up something will try to sort it out hopefully.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #552 from ScrapCodes/SPARK-1565/update-examples and squashes the following commits:

669dd23 [Prashant Sharma] Review comments
2727e70 [Prashant Sharma] SPARK-1565, update examples to be used with spark-submit script.
[SPARK-1745] Move interrupted flag from TaskContext constructor (minor)

It makes little sense to start a TaskContext that is interrupted. Indeed, I searched for all use cases of it and didn't find a single instance in which `interrupted` is true on construction.

This was inspired by reviewing #640, which adds an additional `@volatile var completed` that is similar. These are not the most urgent changes, but I wanted to push them out before I forget.

Author: Andrew Or <andrewor14@gmail.com>

Closes #675 from andrewor14/task-context and squashes the following commits:

9575e02 [Andrew Or] Add space
69455d1 [Andrew Or] Merge branch 'master' of github.com:apache/spark into task-context
c471490 [Andrew Or] Oops, removed one flag too many. Adding it back.
85311f8 [Andrew Or] Move interrupted flag from TaskContext constructor
Fixing typo in als.py

XtY should be Xty.

Author: Evan Sparks <evan.sparks@gmail.com>

Closes #696 from etrain/patch-2 and squashes the following commits:

634cb8d [Evan Sparks] Fixing typo in als.py