Per the discussion in the comments on [this commit](https://github.com/apache/spark/commit/f17d43b033d928dbc46aef8e367aa08902e698ad#commitcomment-10780649), this PR allows the Python lint script to reuse `pep8.py` when possible.

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

Closes #5561 from nchammas/save-dem-pep8-bytes and squashes the following commits:

b7c91e6 [Nicholas Chammas] reuse pep8.py

This PR expands the Python lint checks so that they check for obvious compilation errors in our Python code.

For example:

```
$ ./dev/lint-python
Python lint checks failed.
Compiling ./ec2/spark_ec2.py ...
  File "./ec2/spark_ec2.py", line 618
    return (master_nodes,, slave_nodes)
                         ^
SyntaxError: invalid syntax

./ec2/spark_ec2.py:618:25: E231 missing whitespace after ','
./ec2/spark_ec2.py:1117:101: E501 line too long (102 > 100 characters)
```

This PR also bumps up the version of `pep8`. It ignores new types of checks introduced by that version bump while fixing problems missed by the older version of `pep8` we were using.

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

Closes #4941 from nchammas/compile-spark-ec2 and squashes the following commits:

75e31d8 [Nicholas Chammas] upgrade pep8 + check compile
b33651c [Nicholas Chammas] PEP8 line length

...

Tested ! TBH, it isn't a great idea to have directory with spaces within. Because emacs doesn't like it then hadoop doesn't like it. and so on...

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #2229 from ScrapCodes/SPARK-3337/quoting-shell-scripts and squashes the following commits:

d4ad660 [Prashant Sharma] SPARK-3337 Paranoid quoting in shell to allow install dirs with spaces within.

This PR resolves [SPARK-3361](https://issues.apache.org/jira/browse/SPARK-3361) by expanding the PEP 8 checks to cover the remaining Python code base:
* The EC2 script
* All Python / PySpark examples

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

Closes #2297 from nchammas/pep8-rulez and squashes the following commits:

1e5ac9a [Nicholas Chammas] PEP 8 fixes to Python examples
c3dbeff [Nicholas Chammas] PEP 8 fixes to EC2 script
65ef6e8 [Nicholas Chammas] expand PEP 8 checks

PEP8 tests run on files under "./python", but unzipped py4j code is found at "./python/build/py4j". Py4J code fails style checks and can fail ./dev/run-tests if this code is present locally.

Author: Sean Owen <sowen@cloudera.com>

Closes #2222 from srowen/SPARK-3331 and squashes the following commits:

34711ec [Sean Owen] Restrict lint check to pyspark/, since the local directory can contain unzipped py4j code in build/py4j

As described in [SPARK-2627](https://issues.apache.org/jira/browse/SPARK-2627), we'd like Python code to automatically be checked for PEP 8 compliance by Jenkins. This pull request aims to do that.

Notes:
* We may need to install [`pep8`](https://pypi.python.org/pypi/pep8) on the build server.
* I'm expecting tests to fail now that PEP 8 compliance is being checked as part of the build. I'm fine with cleaning up any remaining PEP 8 violations as part of this pull request.
* I did not understand why the RAT and scalastyle reports are saved to text files. I did the same for the PEP 8 check, but only so that the console output style can match those for the RAT and scalastyle checks. The PEP 8 report is removed right after the check is complete.
* Updates to the ["Contributing to Spark"](https://cwiki.apache.org/confluence/display/SPARK/Contributing+to+Spark) guide will be submitted elsewhere, as I don't believe that text is part of the Spark repo.

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

Closes #1744 from nchammas/master and squashes the following commits:

274b238 [Nicholas Chammas] [SPARK-2627] [PySpark] minor indentation changes
983d963 [nchammas] Merge pull request #5 from apache/master
1db5314 [nchammas] Merge pull request #4 from apache/master
0e0245f [Nicholas Chammas] [SPARK-2627] undo erroneous whitespace fixes
bf30942 [Nicholas Chammas] [SPARK-2627] PEP8: comment spacing
6db9a44 [nchammas] Merge pull request #3 from apache/master
7b4750e [Nicholas Chammas] merge upstream changes
91b7584 [Nicholas Chammas] [SPARK-2627] undo unnecessary line breaks
44e3e56 [Nicholas Chammas] [SPARK-2627] use tox.ini to exclude files
b09fae2 [Nicholas Chammas] don't wrap comments unnecessarily
bfb9f9f [Nicholas Chammas] [SPARK-2627] keep up with the PEP 8 fixes
9da347f [nchammas] Merge pull request #2 from apache/master
aa5b4b5 [Nicholas Chammas] [SPARK-2627] follow Spark bash style for if blocks
d0a83b9 [Nicholas Chammas] [SPARK-2627] check that pep8 downloaded fine
dffb5dd [Nicholas Chammas] [SPARK-2627] download pep8 at runtime
a1ce7ae [Nicholas Chammas] [SPARK-2627] space out test report sections
21da538 [Nicholas Chammas] [SPARK-2627] it's PEP 8, not PEP8
6f4900b [Nicholas Chammas] [SPARK-2627] more misc PEP 8 fixes
fe57ed0 [Nicholas Chammas] removing merge conflict backups
9c01d4c [nchammas] Merge pull request #1 from apache/master
9a66cb0 [Nicholas Chammas] resolving merge conflicts
a31ccc4 [Nicholas Chammas] [SPARK-2627] miscellaneous PEP 8 fixes
beaa9ac [Nicholas Chammas] [SPARK-2627] fail check on non-zero status
723ed39 [Nicholas Chammas] always delete the report file
0541ebb [Nicholas Chammas] [SPARK-2627] call Python linter from run-tests
12440fa [Nicholas Chammas] [SPARK-2627] add Scala linter
61c07b9 [Nicholas Chammas] [SPARK-2627] add Python linter
75ad552 [Nicholas Chammas] make check output style consistent