SPARK-1102: Create a saveAsNewAPIHadoopDataset method

https://spark-project.atlassian.net/browse/SPARK-1102

Create a saveAsNewAPIHadoopDataset method

By @mateiz: "Right now RDDs can only be saved as files using the new Hadoop API, not as "datasets" with no filename and just a JobConf. See http://codeforhire.com/2014/02/18/using-spark-with-mongodb/ for an example of how you have to give a bogus filename. For the old Hadoop API, we have saveAsHadoopDataset."

Author: CodingCat <zhunansjtu@gmail.com>

Closes #12 from CodingCat/SPARK-1102 and squashes the following commits:

6ba0c83 [CodingCat] add test cases for saveAsHadoopDataSet (new&old API)
a8d11ba [CodingCat] style fix.........
95a6929 [CodingCat] code clean
7643c88 [CodingCat] change the parameter type back to Configuration
a8583ee [CodingCat] Create a saveAsNewAPIHadoopDataset method
Update copyright year in NOTICE to 2014

Author: Matei Zaharia <matei@databricks.com>

Closes #174 from mateiz/update-notice and squashes the following commits:

47fc1a5 [Matei Zaharia] Update copyright year in NOTICE to 2014
[SPARK-1260]: faster construction of features with intercept

The current implementation uses `Array(1.0, features: _*)` to construct a new array with intercept. This is not efficient for big arrays because `Array.apply` uses a for loop that iterates over the arguments. `Array.+:` is a better choice here.

Also, I don't see a reason to set initial weights to ones. So I set them to zeros.

JIRA: https://spark-project.atlassian.net/browse/SPARK-1260

Author: Xiangrui Meng <meng@databricks.com>

Closes #161 from mengxr/sgd and squashes the following commits:

b5cfc53 [Xiangrui Meng] set default weights to zeros
a1439c2 [Xiangrui Meng] faster construction of features with intercept
[SPARK-1266] persist factors in implicit ALS

In implicit ALS computation, the user or product factor is used twice in each iteration. Caching can certainly help accelerate the computation. I saw the running time decreased by ~70% for implicit ALS on the movielens data.

I also made the following changes:

1. Change `YtYb` type from `Broadcast[Option[DoubleMatrix]]` to `Option[Broadcast[DoubleMatrix]]`, so we don't need to broadcast None in explicit computation.

2. Mark methods `computeYtY`, `unblockFactors`, `updateBlock`, and `updateFeatures private`. Users do not need those methods.

3. Materialize the final matrix factors before returning the model. It allows us to clean up other cached RDDs before returning the model. I do not have a better solution here, so I use `RDD.count()`.

JIRA: https://spark-project.atlassian.net/browse/SPARK-1266

Author: Xiangrui Meng <meng@databricks.com>

Closes #165 from mengxr/als and squashes the following commits:

c9676a6 [Xiangrui Meng] add a comment about the last products.persist
d3a88aa [Xiangrui Meng] change implicitPrefs match to if ... else ...
63862d6 [Xiangrui Meng] persist factors in implicit ALS
Fix SPARK-1256: Master web UI and Worker web UI returns a 404 error

Author: witgo <witgo@qq.com>

Closes #150 from witgo/SPARK-1256 and squashes the following commits:

08044a2 [witgo] Merge branch 'master' of https://github.com/apache/spark into SPARK-1256
c99b030 [witgo] Fix SPARK-1256
Bundle tachyon:  SPARK-1269

This should all work as expected with the current version of the tachyon tarball (0.4.1)

Author: Nick Lanham <nick@afternight.org>

Closes #137 from nicklan/bundle-tachyon and squashes the following commits:

2eee15b [Nick Lanham] Put back in exec, start tachyon first
738ba23 [Nick Lanham] Move tachyon out of sbin
f2f9bc6 [Nick Lanham] More checks for tachyon script
111e8e1 [Nick Lanham] Only try tachyon operations if tachyon script exists
0561574 [Nick Lanham] Copy over web resources so web interface can run
4dc9809 [Nick Lanham] Update to tachyon 0.4.1
0a1a20c [Nick Lanham] Add scripts using tachyon tarball
Merge github.com:apache/spark

Conflicts:
	core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
	core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
	core/src/main/scala/org/apache/spark/ui/SparkUI.scala