Fix script for graphing entities

PR #1220 simplified the implementation of the `OneToOneField` and
`OneToManyField` classes. Both classes now record which kind of entity they
point to in the instance variable "entity". Formerly, only the `OneToManyField`
did this, and the `OneToOneField` used a variable named "model".

Fix `scripts/graph_entities.py` to deal with this change.
Merge pull request #1226 from Ichimonji10/graph-entities

Fix script for graphing entities
When making API calls, provide "data" not "params"

Then using the requests library (or our wrapper), one can provide the "data" and
"params" arguments. The "data" arguments can be encoded (e.g. as JSON), but the
"params" arguments are encoded directly in a URL.

When communicating with the API, it is sensible to provide all arguments through
a single channel. This change ensures that, whenever possible, all arguments are
passed to the API as JSON-encoded data.
Merge pull request #1227 from Ichimonji10/request-data

When making API calls, provide "data" not "params"
Fix a variety of Sphinx errors

Fix incorrectly delimited code blocks and class references. Nothing special.
Merge pull request #1229 from Ichimonji10/sphinx

Fix a variety of Sphinx errors
Skip known-failing tests

Skip several tests for the System entity. In particular:

* Skip the "delete" test. When a non-existent system is fetched, an HTTP 400 is
  returned instead of an HTTP 404.
* Skip tests which create or update an entity, then read it and verify its
  attributes. When fetching a system, an extremely inconsistent set of results
  is returned.
Merge pull request #1228 from Ichimonji10/jenkins

Skip known-failing tests
Increase logging level

Increase the logging level of easyprocess and pyvirtualdisplay packages
Merge pull request #1230 from elyezer/configure-logging

Increase logging level
Added new `path` to `entities.ContentView`.

Added a new `content_view_puppet_modules` path to `entities.ContentView`
and tests. This will be useful to fetch a list of puppet modules that
are associated to a content view.
Completed more steps for API smoke test.

Added the following steps to the API smoke test:

* Synchronize all repos.
* Associate each repository to a content view
  * Includes associating a random `puppet` module as well.
* Publish content view
* Promote content view to both lifecycle environments
* BONUS: Create a new content host and associate it with promoted
  content view / last lifecycle environment where it lives.

Test passes:

```bash

@Test: Check that basic content can be created ... ok

----------------------------------------------------------------------
Ran 1 test in 109.961s

OK
```
Merge pull request #1233 from omaciel/augmented-smoke

Augmented smoke
test_cv_subscribe_system
test_cv_subscribe_system