Save the command line arguments into a global context

* Once cli args are parsed, they're constant.  So, save the parsed args
  into the global context for everyone else to use them from now on.
* Port cli scripts to use the CLIARGS in the context
* Refactor call to parse cli args into the run() method
* Fix unittests for changes to the internals of CLI arg parsing
* Port callback plugins to use context.CLIARGS
  * Got rid of the private self._options attribute
  * Use context.CLIARGS in the individual callback plugins instead.
  * Also output positional arguments in default and unixy plugins
  * Code has been simplified since we're now dealing with a dict rather
    than Optparse.Value

test/units/test_context.py

@@ -0,0 +1,30 @@
+# -*- coding: utf-8 -*-
+# Copyright: (c) 2018, Toshio Kuratomi <tkuratomi@ansible.com>
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+# Make coding more python3-ish
+from __future__ import (absolute_import, division)
+__metaclass__ = type
+
+
+import pytest
+
+from ansible import context
+
+
+class FakeOptions:
+    pass
+
+
+def test_set_global_context():
+    options = FakeOptions()
+    options.tags = [u'production', u'webservers']
+    options.check_mode = True
+    options.start_at_task = u'Start with くらとみ'
+
+    expected = frozenset((('tags', (u'production', u'webservers')),
+                          ('check_mode', True),
+                          ('start_at_task', u'Start with くらとみ')))
+
+    context._init_global_context(options)
+    assert frozenset(context.CLIARGS.items()) == expected