add a predicate to GraphLab to indicate active vertices at start
vertex should be inactive if no vertices scatter to it
Document missing configs and set shuffle consolidation to false.
Small changes from Matei review
Merge pull request #199 from harveyfeng/yarn-2.2

Hadoop 2.2 migration

Includes support for the YARN API stabilized in the Hadoop 2.2 release, and a few style patches.

Short description for each set of commits:

a98f5a0 - "Misc style changes in the 'yarn' package"
a67ebf4 - "A few more style fixes in the 'yarn' package"
Both of these are some minor style changes, such as fixing lines over 100 chars, to the existing YARN code.

ab8652f - "Add a 'new-yarn' directory ... "
Copies everything from `SPARK_HOME/yarn` to `SPARK_HOME/new-yarn`. No actual code changes here.

4f1c3fa - "Hadoop 2.2 YARN API migration ..."
API patches to code in the `SPARK_HOME/new-yarn` directory. There are a few more small style changes mixed in, too.
Based on @colorant's Hadoop 2.2 support for the scala-2.10 branch in #141.

a1a1c62 - "Add optional Hadoop 2.2 settings in sbt build ... "
If Spark should be built against Hadoop 2.2, then:
a) the `org.apache.spark.deploy.yarn` package will be compiled from the `new-yarn` directory.
b) Protobuf v2.5 will be used as a Spark dependency, since Hadoop 2.2 depends on it. Also, Spark will be built against a version of Akka v2.0.5 that's built against Protobuf 2.5, named `akka-2.0.5-protobuf-2.5`. The patched Akka is here: https://github.com/harveyfeng/akka/tree/2.0.5-protobuf-2.5, and was published to local Ivy during testing.

There's also a new boolean environment variable, `SPARK_IS_NEW_HADOOP`, that users can manually set if their `SPARK_HADOOP_VERSION` specification does not start with `2.2`, which is how the build file tries to detect a 2.2 version. Not sure if this is necessary or done in the best way, though...
Forcing shuffle consolidation in DiskBlockManagerSuite
Always write Vids using variable encoding

Also, autoformat Serializers.scala.
Merge pull request #85 from ankurdave/vid-varenc

Always write Vids using variable encoding
Merge pull request #228 from pwendell/master

Document missing configs and set shuffle consolidation to false.
Finish work on #85
Merge pull request #86 from ankurdave/vid-varenc

Finish work on #85
wip delta join.
In static Pregel, replicate only changed vertices
Test Graph.deltaJoinVertices and VertexRDD.diff
Revert changes to project/SparkBuild.scala

Changes were made in 3fc4534d19a7abf7dcb6c9ebe17e5e29f1febbc5
Fixed a bug that variable encoding doesn't work for ints that use all 64 bits.
Merge pull request #88 from amplab/varenc

Fixed a bug that variable encoding doesn't work for ints that use all 64 bits.
Re-roll last iteration of static Pregel loop
jobWaiter.synchronized before jobWaiter.wait
Change the name of input ragument in ClusterScheduler#initialize from context to backend.

The SchedulerBackend used to be called ClusterSchedulerContext so just want to make small
change of the input param in the ClusterScheduler#initialize to reflect this.