* fixed issue with default callback inheritance
- callbacks need to document same options as callbacks they inherit from to get them configured
- since default is also used by many 3rd party callbacks for inheritance, making the code 'tolerate' the missing docs
and fallback to using the direct constant to configure it's options.
* Using docstrings conflicts with the standard use of docstrings
* PYTHON_OPTIMIZE=2 will omit docstrings. Using docstrings makes future
changes to the plugin and module code subject to the requirement that we
ensure it won't be run with optimization.
* 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