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
vsphere_guest module doc fix
Update playbooks_variables.rst

very small and minor addition, but I couldn't find anywhere that answered this (now obvious) question I had of whether or not facts could also be yaml files.
Do not remove local role file if given on the commandline

using this (for testing purpose) :
  $ ansible-galaxy install COPYING
  - error: the file downloaded was not a tar.gz
  - COPYING was NOT installed successfully.
  - you can use --ignore-errors to skip failed roles.

this result in COPYING being erased, which is surprising for the user.
This also prevent erasing requirements.yml if someone use the wrong flag.
Mention defaults subdirectory in a more visible way

All examples do not show it, so only someone reading the doc from
end to end would know about it.
Merge pull request #8973 from sergevanginderachter/vsphere_guest_docfix

vsphere_guest module doc fix
Merge pull request #8976 from nullren/patch-1

Update playbooks_variables.rst
Merge pull request #8996 from mscherer/improve_doc_defaults

Mention defaults subdirectory in a more visible way
Fix splitting the tag from the image name

Fixes #8983
Ensure checkmode is honored for templates that haven't changed

Fixes #8998
Ensure remote files are chmod'd properly for su/su_user too

Fixes #8594
Do not keep a new file if we fail to set its attributes.
Test that file touch does not keep a new file if we failed to set its
attributes
Merge pull request #8995 from mscherer/fix_galaxy

Do not remove local role file if given on the commandline
Remove duplicate call to remove tmp role file
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