* replaces persistent connection digest with _create_control_path()
* adds _ansible_socket to _legal_inputs in basic.py
* adds connection_user to play_context
* maps remote_user to connection_user when connection is local
* maps ansible_socket in task_vars to module_args _ansible_socket if exists
adds more logging to handle display being called from plugins. Also
rearranges some of the exception handling to better catch exceptions and
log to local syslog
* sends the serialized play_context into an already established connection
* hooks the alarm_handler() method in the connection plugin if it exists
* added configuration options for connect interval and retries
* adds syslog logging to Server() instance
This update will send the updated play_context back into an already
established connection in case privilege escalation / descalation activities
need to be performed. This change will also hook the alarm_handler() method
in the connection instance (if available) and call it in case of a
sigalarm raised.
This update adds two new configuration options
* PERSISTENT_CONNECT_INTERVAL - time to wait in between connection attempts
* PERSISTENT_CONNECT_RETRIES - max number of retries
