Better support for override of parameters that were in vars/

[jostmart]

Since I use the Tinyproxy role from my playbook that are configured with inventory/group_vars and inventory/host_vars I needed override to work on everything inside vars/.

Since inclusion of the files in role vars have higher order of precedence than inventory group_vars or inventory host_vars I moved the content from vars into defaults/.

I then use include files in tasks to support different operating systems.

I added CentOS 7 support.

All boxes in the vagrantfile have OK on the test from within post.yml

[rssnyder]

@tersmitten any update on this? I cannot seem to override tinyproxy_configuration_file without this, which is being set to /etc/tinyproxy.conf in the _default vars but I need to override this to /etc/tinyproxy/tinyproxy.conf as that is the default file for tinyproxy.