* Refactor common network shared and platform specific code into package (part-1)
As per proposal #76 refactor common network shared and platform specific
code into sub-package.
https://github.com/ansible/proposals/issues/76
* ansible.module_utils.network.common - command shared functions
* ansible.module_utils.network.{{ platform }} - where platform is platform specific shared functions
* Fix review comments
* Fix review comments
* 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