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

lib/ansible/plugins/callback/unixy.py

@@ -23,6 +23,7 @@ DOCUMENTATION = '''
 from os.path import basename
 
 from ansible import constants as C
+from ansible import context
 from ansible.module_utils._text import to_text
 from ansible.plugins.callback import CallbackBase
 from ansible.utils.color import colorize, hostcolor
@@ -200,14 +201,16 @@ class CallbackModule(CallbackBase):
         # TODO display whether this run is happening in check mode
         self._display.display("Executing playbook %s" % basename(playbook._file_name))
 
+        # show CLI arguments
         if self._display.verbosity > 3:
-            if self._options is not None:
-                for option in dir(self._options):
-                    if option.startswith('_') or option in ['read_file', 'ensure_value', 'read_module']:
-                        continue
-                    val = getattr(self._options, option)
-                    if val:
-                        self._display.vvvv('%s: %s' % (option, val))
+            if context.CLIARGS.get('args'):
+                self._display.display('Positional arguments: %s' % ' '.join(context.CLIARGS['args']),
+                                      color=C.COLOR_VERBOSE, screen_only=True)
+
+            for argument in (a for a in context.CLIARGS if a != 'args'):
+                val = context.CLIARGS[argument]
+                if val:
+                    self._display.vvvv('%s: %s' % (argument, val))
 
     def v2_runner_retry(self, result):
         msg = "  Retrying... (%d of %d)" % (result._result['attempts'], result._result['retries'])