allow config for callbaks and some fixes

* only complain about ini deprecation if value is set
 * set plugin config for stdout and other types
 * updated plugin docs, moved several plugins to new config
 * finished ssh docs
 * fixed some issues seen in plugins while modifying docs
 * placeholder for 'required'
 * callbacks must use _plugin_options as _options already in use

lib/ansible/plugins/callback/tree.py

@@ -1,20 +1,18 @@
 # (c) 2012-2014, Ansible, Inc
-#
-# This file is part of Ansible
-#
-# Ansible is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Ansible is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
-
+# (c) 2017 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+'''
+DOCUMENTATION:
+    callback: tree
+    callback_type: notification
+    requirements:
+      - invoked in the command line
+    short_description: Save host events to files
+    version_added: "2.0"
+    description:
+        - "This callback is used by the Ansible (adhoc) command line option `-t|--tree`"
+        - This produces a JSON dump of events in a directory, a file for each host, the directory used MUST be passed as a commadn line option.
+'''
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type