are now needed

This commit makes Spark invocation saner by using an assembly JAR to
find all of Spark's dependencies instead of adding all the JARs in
lib_managed. It also packages the examples into an assembly and uses
that as SPARK_EXAMPLES_JAR. Finally, it replaces the old "run" script
with two better-named scripts: "run-examples" for examples, and
"spark-class" for Spark internal classes (e.g. REPL, master, etc). This
is also designed to minimize the confusion people have in trying to use
"run" to run their own classes; it's not meant to do that, but now at
least if they look at it, they can modify run-examples to do a decent
job for them.

As part of this, Bagel's examples are also now properly moved to the
examples package instead of bagel.

- When a resourceOffers() call has multiple offers, force the TaskSets
  to consider them in increasing order of locality levels so that they
  get a chance to launch stuff locally across all offers

- Simplify ClusterScheduler.prioritizeContainers

- Add docs on the new configuration options

Also build and copy ML Lib scaladoc in Spark docs build.
Some more minor cleanup with respect to naming, test locations etc.

Consistently invoke bash with /usr/bin/env bash in scripts to make code more portable (JIRA Ticket SPARK-817)

These typos were reported on the spark-users mailing list, see: https://groups.google.com/d/msg/spark-users/SyLGgJlKCrI/LpeBypOkSMUJ

Conflicts:

	core/src/main/scala/spark/SparkContext.scala