facts caching: fix missing json in jsonfile caching

Need for clarification brought up here:
https://github.com/ansible/ansible/issues/9877

test_git: add tests for `refspec' argument

Fix conditionals doc example

There are still a couple of modules that use their own lists, but that should not prevent this merge, those should be adapted to use this list in subsequent patch

cache json fixes

Use most recent parameters for yum

now uses utils.jsonify which does proper utf8 encoding

Add a explicit error when fact_caching_connection is not set

Add a new inventory group so you can see instances in a particular VPC

By default, jsonfile is not documented, and the error message
when fact_caching_connection is not set is a bit puzzling, so
a error message would be beeter ( documentation too ). While redis
is faster for bigger setup, jsonfile is fine for a small setup
and is easier to deploy.

The module will then stop ansible-playbook, as this match better
the philosophy of Ansible being a fail-fast system.

Includes a basic test of the clone and update cases.

math filters!

already

Fix vars_prompt no/false default values

Do not use the variable name as a key for the result of the module

Make sure ansible-doc work when stdin is not a tty

Request: Honor the "no_proxy" environment variable in Ansible

Strip the line to filter lines composed of only whitespaces

Comment remote_port in the example ansible.cfg so users do not override their .ssh/config settings by default