Use abc for BaseCacheModule

Remove old dead code ( variable no longer exist, not used )

Fix errors reporting for playbook/*

Do add a unused named argument using a variable that was removed

Fix serialize function by using the right members name

Fix variable name

problem that the update fixes:

https://github.com/ansible/ansible-modules-core/issues/1064

Found by pylint.

There is no 'role' variable, and given the test and code after, that's
likely a test on 'ds'

Fix the filename in error message (pylint)

Fix various pylint issues ( missing import and wrong variable names )

Fix the name of the exported class ( pylint )

fixed indent when looking at delegate_to vars

(We have a jenkins build that creates a [testenv:jenkins] so it needs
there to be a default value

Rename the import, since the directory was renamed for v2

Add missing imports. They are used later in mkdtmp, needed by action plu...

Add/correct missing imports for AnsibleError in v2 lookup plugins

Fix the exception name ( AnsibleParserError, not AnsibleParsingError )

Updated the tox.ini file to run multiple ansible versions.

Add a import for 'builtins' module, used in CleansingNodeVisitor.

This was previously done by ./lib/ansible/utils/__init__.py, but
this code is no longer here in v2 anymore. And since the module
got renamed in python3 to builtins ( https://docs.python.org/3/library/builtins.html ),
we have to use six.