Extends the Programs ConfigurationModel, cleans up Programs-related utilities and corresponding tests, and corrects caching. Uses the Programs API to list programs within Studio. ECOM-2769.

Please note that this is a squshed commit and the work of:
Symbolist, macdiesel, nedbat, doctoryes, muzaffaryousaf and muhammad-ammar

This includes:
* Ability to specify number of processes to run bok-choy tests in
* A forked nose commit to get the multiprocess plugin's logging to work
* A different plugin (xunitmp) must be used for pulling together xunit results

This works by:
* Starting the various servers that are needed for the acceptance test environment
* Running the tests themselves in multiprocess mode

* Fix paver violations to stablize edx-lint update
* Parens, Line2Long
* Fix missing docstrings
* Fix PEP8 issues
* Address PR feedback (thanks @nedbat!)

On my devstack, the old line takes about 5.5 seconds, the new line takes
about 1.3 seconds.

For background:
http://nedbatchelder.com/blog/201505/be_careful_deleting_files_around_git.html

This is a squash of 38 commits ending with
5b080f979d692804452400ac5bed9b17c50b001e

This message is being shown to people who should not be deciding whether
to upgrade pip, so it is just confusing and alarming noise.

Before:

---> pavelib.prereqs.install_prereqs
---> pavelib.prereqs.install_ruby_prereqs
Ruby prereqs unchanged, skipping...
---> pavelib.prereqs.install_node_prereqs
Node prereqs unchanged, skipping...
---> pavelib.prereqs.install_python_prereqs
pip install -q --exists-action w -r requirements/edx/pre.txt
You are using pip version 6.0.8, however version 7.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
pip install -q --exists-action w -r requirements/edx/github.txt
You are using pip version 6.0.8, however version 7.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Could not find a tag or branch '96e1922348bfe6d99201b9512a9ed946c87b7e0b', assuming commit.
Could not find a tag or branch 'b0686a76f1ce3532088c4aee6e76b9abe61cc808', assuming commit.
Could not find a tag or branch '88ec8a011e481918fdc9d2682d4017c835acd8be', assuming commit.

After:

---> pavelib.prereqs.install_prereqs
---> pavelib.prereqs.install_ruby_prereqs
Ruby prereqs unchanged, skipping...
---> pavelib.prereqs.install_node_prereqs
Node prereqs unchanged, skipping...
---> pavelib.prereqs.install_python_prereqs
pip install -q --disable-pip-version-check --exists-action w -r requirements/edx/pre.txt
pip install -q --disable-pip-version-check --exists-action w -r requirements/edx/github.txt
Could not find a tag or branch '96e1922348bfe6d99201b9512a9ed946c87b7e0b', assuming commit.
Could not find a tag or branch 'b0686a76f1ce3532088c4aee6e76b9abe61cc808', assuming commit.
Could not find a tag or branch '88ec8a011e481918fdc9d2682d4017c835acd8be', assuming commit.

I want to make clear that these tests rely on XBlocks in other repos,
and that ideally in time we would move these tests into the XBlock repo.

[Also correct some comments.]

The platform includes jshint as a development tool, and our
builds are enforcing a limit on total number of jshint violations.
This commit will enforce no new jshint violations on a per-change
basis, much like pylint and pep8 are enforced. So with this change,
we'll be enforcing our linting requirements consistently, regardless
of type of violations.

Also on Jenkins, runs quality task after installing jshint.

This is the default in 3.2, but will need to be explicitly stated in
Sass 3.4.

Also, added a --force parameter to compile_sass to make it easier to see
what warnings are current.

The old line:

    from path import path

produced pylint errors because of the baroque way that path.py defined
"path".  We tried to get them to change how they defined it, but they
deleted the name instead: https://github.com/jaraco/path.py/issues/102

(Jason then changed his mind, but this is a better way to use path.py,
it avoids the pylint error at least.)

This reverts commit 2ff0f636.

This complexity metric is created by using radon (see changed files for additional
documentation links). This tool calculates cyclomatic complexity and provides a numeric grade
where a lower number is better (e.g., less complex).