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/timer.py

@@ -1,3 +1,16 @@
+# (c) 2017 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+'''
+DOCUMENTATION:
+    callback: timer
+    callback_type: aggregate
+    requirements:
+      - whitelist in configuration
+    short_description: Adds time to play stats
+    version_added: "2.0"
+    description:
+        - This callback just adds total play duration to the play stats.
+'''
 # Make coding more python3-ish
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type