* WIP update asa to use network_cli connection plugin
* add asa.py to cliconf plugins
* update asa.py terminal plugin to support regexp and events
* update constants to map asa modules to asa action handler
* update asa action handler to implement persistent connections
* update asa shared module to use persistent connections
* update asa_command module to use new connection
* fixed pep8 issues
* removes unneeded supports_multiplexing var
* refactors terminal_prompts_re to terminal_stdout_re
* refactors terminal_errors_re to terminal_stderr_re
* updates network_cli unit test cases
* adds new connection plugin `network_cli` which builds on paramiko
* adds new plugin `terminal` used for manipulating network_cli terminals
* adds new field to play_context `network_os` settable as ansible_network_os
This commit adds the plugins necesary to establish a persistent cli connection
to network devices of ssh. It builds on the paramiko connection plugin
to create a shell environment that will persistent through ansible-connection.
The `newtork_cli` plugin then uses the network_os in the instance of
PlayContext to load the appropriate network OS environment plugin for
handling opening and closing of shells as well as privilege escalation.
Jacob McGill
Patrick Ogenstad
Peter Sprygada
Dag Wieers