Fixed coding style issues in Spark SQL

This PR addresses various coding style issues in Spark SQL, including but not limited to those mentioned by @mateiz in PR #146.

As this PR affects lots of source files and may cause potential conflicts, it would be better to merge this as soon as possible *after* PR #205 (In-memory columnar representation for Spark SQL) is merged.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #208 from liancheng/fixCodingStyle and squashes the following commits:

fc2b528 [Cheng Lian] Merge branch 'master' into fixCodingStyle
b531273 [Cheng Lian] Fixed coding style issues in sql/hive
0b56f77 [Cheng Lian] Fixed coding style issues in sql/core
fae7b02 [Cheng Lian] Addressed styling issues mentioned by @marmbrus
9265366 [Cheng Lian] Fixed coding style issues in sql/core
3dcbbbd [Cheng Lian] Fixed relative package imports for package catalyst
[SPARK-1212] Adding sparse data support and update KMeans

Continue our discussions from https://github.com/apache/incubator-spark/pull/575

This PR is WIP because it depends on a SNAPSHOT version of breeze.

Per previous discussions and benchmarks, I switched to breeze for linear algebra operations. @dlwh and I made some improvements to breeze to keep its performance comparable to the bare-bone implementation, including norm computation and squared distance. This is why this PR needs to depend on a SNAPSHOT version of breeze.

@fommil , please find the notice of using netlib-core in `NOTICE`. This is following Apache's instructions on appropriate labeling.

I'm going to update this PR to include:

1. Fast distance computation: using `\|a\|_2^2 + \|b\|_2^2 - 2 a^T b` when it doesn't introduce too much numerical error. The squared norms are pre-computed. Otherwise, computing the distance between the center (dense) and a point (possibly sparse) always takes O(n) time.

2. Some numbers about the performance.

3. A released version of breeze. @dlwh, a minor release of breeze will help this PR get merged early. Do you mind sharing breeze's release plan? Thanks!

Author: Xiangrui Meng <meng@databricks.com>

Closes #117 from mengxr/sparse-kmeans and squashes the following commits:

67b368d [Xiangrui Meng] fix SparseVector.toArray
5eda0de [Xiangrui Meng] update NOTICE
67abe31 [Xiangrui Meng] move ArrayRDDs to mllib.rdd
1da1033 [Xiangrui Meng] remove dependency on commons-math3 and compute EPSILON directly
9bb1b31 [Xiangrui Meng] optimize SparseVector.toArray
226d2cd [Xiangrui Meng] update Java friendly methods in Vectors
238ba34 [Xiangrui Meng] add VectorRDDs with a converter from RDD[Array[Double]]
b28ba2f [Xiangrui Meng] add toArray to Vector
e69b10c [Xiangrui Meng] remove examples/JavaKMeans.java, which is replaced by mllib/examples/JavaKMeans.java
72bde33 [Xiangrui Meng] clean up code for distance computation
712cb88 [Xiangrui Meng] make Vectors.sparse Java friendly
27858e4 [Xiangrui Meng] update breeze version to 0.7
07c3cf2 [Xiangrui Meng] change Mahout to breeze in doc use a simple lower bound to avoid unnecessary distance computation
6f5cdde [Xiangrui Meng] fix a bug in filtering finished runs
42512f2 [Xiangrui Meng] Merge branch 'master' into sparse-kmeans
d6e6c07 [Xiangrui Meng] add predict(RDD[Vector]) to KMeansModel
42b4e50 [Xiangrui Meng] line feed at the end
a4ace73 [Xiangrui Meng] Merge branch 'fast-dist' into sparse-kmeans
3ed1a24 [Xiangrui Meng] add doc to BreezeVectorWithSquaredNorm
0107e19 [Xiangrui Meng] update NOTICE
87bc755 [Xiangrui Meng] tuned the KMeans code: changed some for loops to while, use view to avoid copying arrays
0ff8046 [Xiangrui Meng] update KMeans to use fastSquaredDistance
f355411 [Xiangrui Meng] add BreezeVectorWithSquaredNorm case class
ab74f67 [Xiangrui Meng] add fastSquaredDistance for KMeans
4e7d5ca [Xiangrui Meng] minor style update
07ffaf2 [Xiangrui Meng] add dense/sparse vector data models and conversions to/from breeze vectors use breeze to implement KMeans in order to support both dense and sparse data
fail all jobs when DAGScheduler crashes for some reason
logging error reason
minimize the influence to the jobs
kill application when the exception was thrown
check if DAGScheduler is shutdown in SparkContext
style fix
add test case