Add support for filtering EC2 instances in dynamic inventory

This allows filtering out EC2 instances based on various different
filters including tags. As requested in 7480 it supports logical "OR"
instead of "AND" on the provided list of filters.
Exit with rc 1 if role doesn't exist/is not found

fixes #8823
	modified:   bin/ansible-galaxy
Document vault_password_file in intro_configuration
Also document force_color
rearrange description/short_description

it's really dorked on [the documentation page](http://docs.ansible.com/ec2_elb_lb_module.html). This puts it in line with other modules.
further cleanup
Make systemd vs rht detection more robust for centos

Centos 6.x and below use an old RHT style of configuring hostname.
CentOS 7.x and better use systemd.  Instead of depending on the
distribution string which seems to have changed over the course of 6.x
we need to explicitly check the version.

Fixes #8997
updated git module documentation

Clarified key_file option for the git module, since it requires the user to specify a private key, not a public key.
Adding "follow" param for file/copy options

Also modifies the template action plugin to use this new param
when executing the file/copy modules for templating so that links
are preserved correctly.

Fixes #8998
Add note to ec2_vol state param regarding list option added in 1.8
Fix the case where a docker image is not part of a namespace.

Fixes #9016
My fix was wrong again.  Base this try off of @mantiz's fix in #9016
Merge pull request #9025 from sivel/doc-vault-password-file

Document vault_password_file in intro_configuration
Merge pull request #9026 from tedder/patch-1

rearrange description/short_description
Merge pull request #9028 from dhoss/devel

updated git module documentation
Allow hostvars variables to be templated

Fixes #7844
Fix documentation indent levels.
Docs indentation - this time with feeling
Merge branch 'ec2-tag-filter' of https://github.com/michalgasek/ansible into michalgasek-ec2-tag-filter
Merge branch 'michalgasek-ec2-tag-filter' into devel