[SPARK-4529] [SQL] support view with column alias

Support view definition like

CREATE VIEW view3(valoo)
TBLPROPERTIES ("fear" = "factor")
AS SELECT upper(value) FROM src WHERE key=86;

[valoo as the alias of upper(value)]. This is missing part of SPARK-4239, for a fully view support.

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #3396 from adrian-wang/viewcolumn and squashes the following commits:

4d001d0 [Daoyuan Wang] support view with column alias
[SPARK-4268][SQL] Use #::: to get benefit from Stream in SqlLexical.allCaseVersions

In addition, using `s.isEmpty` to eliminate the string comparison.

Author: zsxwing <zsxwing@gmail.com>

Closes #3132 from zsxwing/SPARK-4268 and squashes the following commits:

358e235 [zsxwing] Improvement of allCaseVersions
MAINTENANCE: Automated closing of pull requests.

This commit exists to close the following pull requests on Github:

Closes #1612 (close requested by 'marmbrus')
Closes #2723 (close requested by 'marmbrus')
Closes #1737 (close requested by 'marmbrus')
Closes #2252 (close requested by 'marmbrus')
Closes #2029 (close requested by 'marmbrus')
Closes #2386 (close requested by 'marmbrus')
Closes #2997 (close requested by 'marmbrus')
[SPARK-4611][MLlib] Implement the efficient vector norm

The vector norm in breeze is implemented by `activeIterator` which is known to be very slow.
In this PR, an efficient vector norm is implemented, and with this API, `Normalizer` and
`k-means` have big performance improvement.

Here is the benchmark against mnist8m dataset.

a) `Normalizer`
Before
DenseVector: 68.25secs
SparseVector: 17.01secs

With this PR
DenseVector: 12.71secs
SparseVector: 2.73secs

b) `k-means`
Before
DenseVector: 83.46secs
SparseVector: 61.60secs

With this PR
DenseVector: 70.04secs
SparseVector: 59.05secs

Author: DB Tsai <dbtsai@alpinenow.com>

Closes #3462 from dbtsai/norm and squashes the following commits:

63c7165 [DB Tsai] typo
0c3637f [DB Tsai] add import org.apache.spark.SparkContext._ back
6fa616c [DB Tsai] address feedback
9b7cb56 [DB Tsai] move norm to static method
0b632e6 [DB Tsai] kmeans
dbed124 [DB Tsai] style
c1a877c [DB Tsai] first commit
[SPARK-4397][Core] Cleanup 'import SparkContext._' in core

This PR cleans up `import SparkContext._` in core for SPARK-4397(#3262) to prove it really works well.

Author: zsxwing <zsxwing@gmail.com>

Closes #3530 from zsxwing/SPARK-4397-cleanup and squashes the following commits:

04e2273 [zsxwing] Cleanup 'import SparkContext._' in core
[SPARK-4686] Link to allowed master URLs is broken

The link points to the old scala programming guide; it should point to the submitting applications page.

This should be backported to 1.1.2 (it's been broken as of 1.0).

Author: Kay Ousterhout <kayousterhout@gmail.com>

Closes #3542 from kayousterhout/SPARK-4686 and squashes the following commits:

a8fc43b [Kay Ousterhout] [SPARK-4686] Link to allowed master URLs is broken
Indent license header properly for interfaces.scala.

A very small nit update.

Author: Reynold Xin <rxin@databricks.com>

Closes #3552 from rxin/license-header and squashes the following commits:

df8d1a4 [Reynold Xin] Indent license header properly for interfaces.scala.
[SPARK-4536][SQL] Add sqrt and abs to Spark SQL DSL

Spark SQL has embeded sqrt and abs but DSL doesn't support those functions.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #3401 from sarutak/dsl-missing-operator and squashes the following commits:

07700cf [Kousuke Saruta] Modified Literal(null, NullType) to Literal(null) in DslQuerySuite
8f366f8 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into dsl-missing-operator
1b88e2e [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into dsl-missing-operator
0396f89 [Kousuke Saruta] Added sqrt and abs to Spark SQL DSL
[SPARK-4663][sql]add finally to avoid resource leak

Author: baishuo <vc_java@hotmail.com>

Closes #3526 from baishuo/master-trycatch and squashes the following commits:

d446e14 [baishuo] correct the code style
b36bf96 [baishuo] correct the code style
ae0e447 [baishuo] add finally to avoid resource leak