Clean up Ansible 2.0 release notes in CHANGELOG.md.

Fixes #12331

Fixes #12333

Fixes #12238

Revert "Fix order of loading of modules."

Hi @amenonsen - thanks for fixing up the hunting down the unicode bug and expanding test_addresses.  The code looks good, merging!-- Be systematic about parsing and validating hostnames and addresses

This reverts commit 4b895f04.

Test state.tasks_child_state before dereferencing

I hit a traceback in the FAILED_TASKS case, but it seemed prudent to add
guards in the other similar branches.

These used to go in vars_cache, so merging them in after that as they
are "live" variables and the user would most likely want to see these
above anything else.

1. The test did "name: '{{hostnames}}.{{item}}'" inside a with_sequence
   loop, which didn't do what was intended: it expanded hostnames into
   an array, appended ".1", and set name to the resulting string. This
   can be converted to a simple with_items loop.

2. Some of the entries in hostnames contained punctuation characters,
   which I see no reason to support in inventory hostnames anyway.

3. Once the add_host failures are fixed, the playbook later fails when
   the unicode hostnames are interpolated into debug output in ssh.py
   due to an encoding error. This is only one of the many places that
   may fail when using unicode inventory hostnames; we work around it
   by providing an ansible_ssh_host setting.

Labels must start with an alphanumeric character, may contain
alphanumeric characters or hyphens, but must not end with a hyphen.
We enforce those rules, but allow underscores wherever hyphens are
accepted, and allow alphanumeric ranges anywhere.

We relax the definition of "alphanumeric" to include Unicode characters
even though such inventory hostnames cannot be used in practice unless
an ansible_ssh_host is set for each of them.

We still don't enforce length restrictions—the fact that we have to
accept ranges makes it more complex, and it doesn't seem especially
worthwhile.

This adds a parse_address(pattern) utility function that returns
(host,port), and uses it wherever where we accept IPv4 and IPv6
addresses and hostnames (or host patterns): the inventory parser
the the add_host action plugin.

It also introduces a more extensive set of unit tests that supersedes
the old add_host unit tests (which didn't actually test add_host, but
only the parsing function).

Fixes #12327

Python 3: make ansible.template.safe_eval() work

Test for Python must be against basename of interpreter

This reverts commit 926f1272.

Followup on issue #12076

Add the new module replacer <<INCLUDE_ANSIBLE_MODULE_JSON_ARGS>>.

There was code to support set literals (on Python 2.7 and newer), but it
was buggy: SAFE_NODES.union() doesn't modify SAFE_NODES in place,
instead it returns a new set object that is then silently discarded.

I added a unit test and fixed the code.  I also changed the version
check to use sys.version_tuple instead of a string comparison, for
consistency with the subsequent Python 3.4 version check that I added in
the previous commit.

Two things changed in Python 3.4:

- 'basestring' is no longer defined, so use six.string_types

- True/False are now special AST node types (NamedConstant) rather than
  just names

(Good thing we had tests, or I wouldn't have noticed the 2nd thing!)

I found only one place where safe_eval() is called inside the ansible
codebase: in lib/template/__init__.py.  The call to safe_eval(result,
...) is protected by result.startswith('...'), which means result cannot
possibly be a byte string on Python 3 (or startswith() would raise, so
six.string_types (which excludes byte strings on Python 3) is fine here.

Fixes #12314

cloudstack: new integration test role test_cs_user

Fixes #12313

Required as part of fix for #12123

Fixes #12123

Rename ansible_ssh_{host,port,user} in docs to ansible_*

The _ssh variants will continue to work, but the shorter, more generic
names are preferred now.

Doc fixes