Merge remote-tracking branch 'origin/develop' into develop

* origin/develop:
  The documentation for 'Developing Salt' is missing a critical step for 0.17+ users who wish to utilize the test runner. This commit describes the direct installation of salt-testing.
  -- Please review for accuracy prior to merge --
Expand the `pip` library requirement.
Fix issue 5951 - correct __opts__['file_roots'] in ext_pillars
Merge pull request #7768 from terminalmage/docs

Docstring fixes
Merge pull request #7763 from s0undt3ch/develop

Expand the `pip` library requirement.
Merge pull request #7767 from dlanderson/fix_issue_5951

Fix issue 5951 - correct __opts__['file_roots'] in ext_pillars
Merge branch 'develop' of https://github.com/saltstack/salt into develop

* 'develop' of https://github.com/saltstack/salt: (193 commits)
  Docstring fixes
  Fix issue 5951 - correct __opts__['file_roots'] in ext_pillars
  Expand the `pip` library requirement.
  mention LocalClient.cmd "kwarg" argument in docs
  Added undocumented ssh roster configuration options
  Explain why the pip state needs a pip module importable. Refs #7659.
  except right exception that file module raised
  Prettify subcommand to kill minions
  Removed special case for uppercase attributes from Mock object
  Updated Sphinx makefile for latest Sphinx and i18n additions
  [3665] do not persist gitfs cache dir after config change/restart
  refer to appropriate class (self) in the Caller docstring
  Fixed typo in comment
  Fixed typos and bugs in hgfs. Fixes #7687
  Restore the pillar[master][file_roots] when returning the pillar
  Fix typo
  Have the minion actually generate its ID
  rm unused imports from states/win_system.py
  tomcat module: rm trailing whitespace
  rename code:: to code-block::
  ...
Add support for other documentation languages.
Add the translatable files for the `zh_CN` translation.
Remove pillar matching for mine.get
Fix `.PHONY` target
Cosmetic adjustment to add some color to the output of sys.doc.
Fix yaml.load refs

These are not really security issues because Salt parses all
incomming arguments via yaml.safe_load before they get here, these
really are not needed. I kept the yaml check in for pillar.ext
simply because we want to be able to support an internal application
firing the routine with a yaml sting.
single quotes
Drop suplimetary groups when running an non-root user
Fix command injection vulnerability in disk.usage
It is better to die(), than to return falsely.
Merge pull request #7774 from techhat/cmdinjection

Fix command injection vulnerability in disk.usage
Merge pull request #7770 from basepi/minepillar7197

Remove pillar matching for mine.get
Merge pull request #7771 from cachedout/develop

Adding some color to sys.doc