[SPARK-3777] Display "Executor ID" for Tasks in Stage page

Now the Stage page only displays "Executor"(host) for tasks. However, there may be more than one Executors running in the same host. Currently, when some task is hung, I only know the host of the faulty executor. Therefore I have to check all executors in the host.

Adding "Executor ID" in the Tasks table. would be helpful to locate the faulty executor. Here is the new page:

![add_executor_id_for_tasks](https://cloud.githubusercontent.com/assets/1000778/4505774/acb9648c-4afa-11e4-8826-8768a0a60cc9.png)

Author: zsxwing <zsxwing@gmail.com>

Closes #2642 from zsxwing/SPARK-3777 and squashes the following commits:

37945af [zsxwing] Put Executor ID and Host into one cell
4bbe2c7 [zsxwing] [SPARK-3777] Display "Executor ID" for Tasks in Stage page
[SPARK-3790][MLlib] CosineSimilarity Example

Provide example  for `RowMatrix.columnSimilarity()`

Author: Reza Zadeh <rizlar@gmail.com>

Closes #2622 from rezazadeh/dimsumexample and squashes the following commits:

8f20b82 [Reza Zadeh] update comment
379066d [Reza Zadeh] cache rows
792b81c [Reza Zadeh] Address review comments
e573c7a [Reza Zadeh] Average absolute error
b15685f [Reza Zadeh] Use scopt. Distribute evaluation.
eca3dfd [Reza Zadeh] Documentation
ac96fb2 [Reza Zadeh] Compute approximation error, add command line.
4533579 [Reza Zadeh] CosineSimilarity Example
[SPARK-3486][MLlib][PySpark] PySpark support for Word2Vec

mengxr
Added PySpark support for Word2Vec
Change list
(1) PySpark support for Word2Vec
(2) SerDe support of string sequence both on python side and JVM side
(3) Test for SerDe of string sequence on JVM side

Author: Liquan Pei <liquanpei@gmail.com>

Closes #2356 from Ishiihara/Word2Vec-python and squashes the following commits:

476ea34 [Liquan Pei] style fixes
b13a0b9 [Liquan Pei] resolve merge conflicts and minor fixes
8671eba [Liquan Pei] Merge remote-tracking branch 'upstream/master' into Word2Vec-python
daf88a6 [Liquan Pei] modification according to feedback
a73fa19 [Liquan Pei] clean up
3d8007b [Liquan Pei] fix findSynonyms for vector
1bdcd2e [Liquan Pei] minor fixes
cdef9f4 [Liquan Pei] add missing comments
b7447eb [Liquan Pei] modify according to feedback
b9a7383 [Liquan Pei] cache words RDD in fit
89490bf [Liquan Pei] add tests and Word2VecModelWrapper
78bbb53 [Liquan Pei] use pickle for seq string SerDe
a264b08 [Liquan Pei] Merge remote-tracking branch 'upstream/master' into Word2Vec-python
ca1e5ff [Liquan Pei] fix test
68e7276 [Liquan Pei] minor style fixes
48d5e72 [Liquan Pei] Functionality improvement
0ad3ac1 [Liquan Pei] minor fix
c867fdf [Liquan Pei] add Word2Vec to pyspark
[SPARK-3832][MLlib] Upgrade Breeze dependency to 0.10

In Breeze 0.10, the L1regParam can be configured through anonymous function in OWLQN, and each component can be penalized differently. This is required for GLMNET in MLlib with L1/L2 regularization.
https://github.com/scalanlp/breeze/commit/2570911026aa05aa1908ccf7370bc19cd8808a4c

Author: DB Tsai <dbtsai@dbtsai.com>

Closes #2693 from dbtsai/breeze0.10 and squashes the following commits:

7a0c45c [DB Tsai] In Breeze 0.10, the L1regParam can be configured through anonymous function in OWLQN, and each component can be penalized differently. This is required for GLMNET in MLlib with L1/L2 regularization. https://github.com/scalanlp/breeze/commit/2570911026aa05aa1908ccf7370bc19cd8808a4c
[SPARK-3398] [EC2] Have spark-ec2 intelligently wait for specific cluster states

Instead of waiting arbitrary amounts of time for the cluster to reach a specific state, this patch lets `spark-ec2` explicitly wait for a cluster to reach a desired state.

This is useful in a couple of situations:
* The cluster is launching and you want to wait until SSH is available before installing stuff.
* The cluster is being terminated and you want to wait until all the instances are terminated before trying to delete security groups.

This patch removes the need for the `--wait` option and removes some of the time-based retry logic that was being used.

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes #2339 from nchammas/spark-ec2-wait-properly and squashes the following commits:

43a69f0 [Nicholas Chammas] short-circuit SSH check; linear backoff
9a9e035 [Nicholas Chammas] remove extraneous comment
26c5ed0 [Nicholas Chammas] replace print with write()
bb67c06 [Nicholas Chammas] deprecate wait option; remove dead code
7969265 [Nicholas Chammas] fix long line (PEP 8)
126e4cf [Nicholas Chammas] wait for specific cluster states
[SPARK-3829] Make Spark logo image on the header of HistoryPage as a link to HistoryPage's page #1

There is a Spark logo on the header of HistoryPage.
We can have too many HistoryPages if we run 20+ applications. So I think, it's useful if the logo is as a link to the HistoryPage's page number 1.

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

Closes #2690 from sarutak/SPARK-3829 and squashes the following commits:

908c109 [Kousuke Saruta] Removed extra space.
00bfbd7 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-3829
dd87480 [Kousuke Saruta] Made header Spark log image as a link to History Server's top page.
[SPARK-3412] [PySpark] Replace Epydoc with Sphinx to generate Python API docs

Retire Epydoc, use Sphinx to generate API docs.

Refine Sphinx docs, also convert some docstrings into Sphinx style.

It looks like:
![api doc](https://cloud.githubusercontent.com/assets/40902/4538272/9e2d4f10-4dec-11e4-8d96-6e45a8fe51f9.png)

Author: Davies Liu <davies.liu@gmail.com>

Closes #2689 from davies/docs and squashes the following commits:

bf4a0a5 [Davies Liu] fix links
3fb1572 [Davies Liu] fix _static in jekyll
65a287e [Davies Liu] fix scripts and logo
8524042 [Davies Liu] Merge branch 'master' of github.com:apache/spark into docs
d5b874a [Davies Liu] Merge branch 'master' of github.com:apache/spark into docs
4bc1c3c [Davies Liu] refactor
746d0b6 [Davies Liu] @param -> :param
240b393 [Davies Liu] replace epydoc with sphinx doc