* Fixes extra spaces added between parameters from https://github.com/ansible/ansible-modules-core/issues/1929
* Correctly decode PowerShell command encoded as UTF-16-LE so that it displays correctly in debug messages, fixes the other issue from https://github.com/ansible/ansible-modules-core/issues/1929
* Add test to verify that script parameters are passed as-is, so $true is interpreted as a boolean, fixes https://github.com/ansible/ansible/issues/10947

* Add exception handling when running PowerShell modules to provide exception message and stack trace.
* Enable strict mode for all PowerShell modules and internal commands.
* Update common PowerShell code to fix strict mode errors.
* Fix an issue with Set-Attr where it would not replace an existing property if already set.
* Add tests for exception handling using modified win_ping modules.

Fix fetch action plugin to not fail if file is missing and fail_if_missing=False (the default).  Add tests to test_fetch role to verify it works as expected.

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.

`assert (condition, message)` gets parsed by Python as `assert
a_two_tuple`, and a 2-element tuple is never False.

Discovered by compileall on Python 3.4, which emits a SyntaxWarning for
this common mistake.

Fixes #11981
Fixes #11995
Fixes #12039
Fixes #12077

added block environment test

* Add exception handling when running PowerShell modules to provide exception message and stack trace.
* Enable strict mode for all PowerShell modules and internal commands.
* Update common PowerShell code to fix strict mode errors.
* Fix an issue with Set-Attr where it would not replace an existing property if already set.
* Add tests for exception handling using modified win_ping modules.

This change is similar to https://github.com/ansible/ansible/pull/10465

It extends the logic there to also support none types.  Right now if you have
a '!!null' in yaml, and that var gets passed around, it will get converted to
a string.

eg. defaults/main.yml
```
ENABLE_AWESOME_FEATURE: !!null # Yaml Null
OTHER_CONFIG:
  secret1: "so_secret"
  secret2: "even_more_secret"

CONFIG:
  hostname: "some_hostname"
  features:
    awesame_feature: "{{ ENABLE_AWESOME_FEATURE}}"
  secrets: "{{ OTHER_CONFIG }}"
```

If you output `CONFIG` to json or yaml, the feature flag would get represented in the output
as a string instead of as a null, but secrets would get represented as a dictionary.  This is
a mis-match in behaviour where some "types" are retained and others are not.  This change
should fix the issue.

I also updated the template test to test for this and made the changes to v2.

Added a changelog entry specifically for the change from empty string to null as the default.

Made the null representation configurable.

It still defaults to the python NoneType but can be overriden to be an emptystring by updating
the DEFAULT_NULL_REPRESENTATION config.

fixes #11979