tags lists are properly uniqued and joined now

Signed-off-by: Brian Coca <briancoca+ansible@gmail.com>

tags lists are properly uniqued and joined now, also avoids type issues when passed as list/set or strings

Signed-off-by: Brian Coca <briancoca+ansible@gmail.com>

Fixes #6047

Update debian install documentation to include dependency resolution

Update playbooks_vault.rst

Keep track of role dependencies across plays

This reverts commit a8082874, reversing
changes made to 6129ea75.

Also fixes a bug in which tags specified on top-level roles were
not being passed down to dependent roles.

Fixes #4656

Fix inventory for test_dir_inventory, merge PRs from GH-5749, cleanup some formatting.

closes #5749

Conflicts:
	test/units/TestInventory.py

tests issue #5749
 same host defined in different groups which in turn are defined
 in different ini files in an inventory directory

Conflicts:
	test/units/TestInventory.py

Add option to enable the sysctl -e option

very minor grammatical fix for readability

fixes #6244

Add credential parameters to the GCE modules.

In order to simplify the workflow with the GCE modules, it's now
possible to add the parameters and project name as arguments to the
various GCE modules.

The inventory plugin also returns the IP of the host in
`ansible_ssh_host` so that you don't have to specify IPs into the
inventory file.

Some update to the documentation are also added.

Closes #5583.

It came up that fixing this unit test may relate to another ticket that is open. This work allows us to uncomment this unit test by fixing how we pars variables allowing a quoted variable to contain a '#'.

Work also went into cleaning up some of the test data to clarify what was working.

Lastly work went into cleaning up formatting so that the code is easily read.

Update intro_installation.rst

Fix broken Ansible Tower link.

error in ubuntu install instructions

setup: Fix KeyError: 'ipv4_secondaries' (issue #6274)

Fix wrong module name for exception in nova compute

Fixed Links

Link to guru page was not rendering correctly on http://docs.ansible.com/faq.html.
Link to readme returned 404.

Update README.md

ansible depends on sshpass as well.

  failed: [127.0.0.1] => {"failed": true, "parsed": false}
  invalid output was: Traceback (most recent call last):
    File "/tmp/ansible-tmp-1393950384.39-102240090845592/nova_compute", line 1328, in <module>
      main()
    File "/tmp/ansible-tmp-1393950384.39-102240090845592/nova_compute", line 241, in main
      except exc.Unauthorized, e:
  NameError: global name 'exc' is not defined