Fix list rendering in YARN markdown docs.

This is some minor clean-up which makes the list render correctly.

Expose numPartitions parameter in JavaPairRDD.sortByKey()

This change makes Java and Scala API on sortByKey() the same.

Migration to Scala 2.10

== Below description was written by Prashant Sharma ==

This PR migrates spark to scala 2.10.

Summary of changes apart from scala 2.10 migration:
(has no implications for user.)
1. Migrated Akka to 2.2.3.

Does not use remote death watch for it has a bug, where it tries to send message to dead node infinitely.

Uses an indestructible actorsystem which tolerates errors only on executors.

(Might be useful for user.)
4. New configuration settings introduced:

System.getProperty("spark.akka.heartbeat.pauses", "600")
System.getProperty("spark.akka.failure-detector.threshold", "300.0")
System.getProperty("spark.akka.heartbeat.interval", "1000")

Defaults for these are fairly large to only disable Failure detector that comes with akka. The reason for doing so is we have our own failure detector like mechanism in place and then this is just an overhead on top of that + it leads to a lot of false positives. But with these properties it is possible to enable them. A good use case for enabling it could be when someone wants spark to be sensitive (in a controllable manner ofc.) to GC pauses/Network lags and quickly evict executors that experienced it. More information is included in configuration.md

Once we have the SPARK-544 merged, I had like to deprecate atleast these akka properties and may be others too.

This PR is duplicate of #221(where all the discussion happened.) for that one pointed to master this one points to scala-2.10 branch.

Fix maven build issues in 2.10 branch

Found some issues when locally testing maven.

Added a comment about ActorRef and ActorSelection difference.

Review comments on the PR for scala 2.10 migration.

Disabled yarn 2.2 in sbt and mvn build and added a message in the sbt build.

Scala 2.10 migration

This PR migrates spark to scala 2.10.

Summary of changes apart from scala 2.10 migration:
(has no implications for user.)
1. Migrated Akka to 2.2.3.

Does not use remote death watch for it has a bug, where it tries to send message to dead node infinitely.

Uses an indestructible actorsystem which tolerates errors only on executors.

(Might be useful for user.)
4. New configuration settings introduced:

System.getProperty("spark.akka.heartbeat.pauses", "600")
System.getProperty("spark.akka.failure-detector.threshold", "300.0")
System.getProperty("spark.akka.heartbeat.interval", "1000")

Defaults for these are fairly large to only disable Failure detector that comes with akka. The reason for doing so is we have our own failure detector like mechanism in place and then this is just an overhead on top of that + it leads to a lot of false positives. But with these properties it is possible to enable them. A good use case for enabling it could be when someone wants spark to be sensitive (in a controllable manner ofc.) to GC pauses/Network lags and quickly evict executors that experienced it. More information is included in configuration.md

Once we have the SPARK-544 merged, I had like to deprecate atleast these akka properties and may be others too.

This PR is duplicate of #221(where all the discussion happened.) for that one pointed to master this one points to scala-2.10 branch.

Conflicts:
	core/pom.xml
	core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
	pom.xml
	project/SparkBuild.scala
	streaming/pom.xml
	yarn/src/main/scala/org/apache/spark/deploy/yarn/YarnAllocationHandler.scala

README incorrectly suggests build sources spark-env.sh

This is misleading because the build doesn't source that file. IMO
it's better to force people to specify build environment variables
on the command line always, like we do in every example, so I'm
just removing this doc.

This is misleading because the build doesn't source that file. IMO
it's better to force people to specify build environment variables
on the command line always, like we do in every example.

This change make Java and Scala API on sortByKey() the same.

Add missing license headers

I found this when doing further audits on the 0.8.1 release candidate.

[Deb] fix package of Spark classes adding org.apache prefix in scripts embeded in .deb

Update broken links and add HDP 2.0 version string

I ran a link checker on the UI and found several broken links.

SPARK-917 Improve API links in nav bar

Correct spellling error in configuration.md

Incorporated Patrick's feedback comment on #211 and made maven build/dep-resolution atleast a bit faster.

Formatting fix

This is a single-line change. The diff appears larger here due to github being out of sync.

Adding disclaimer for shuffle file consolidation