Make `pip install -e` work

This allows `pip install -e` and `python setup.py develop` to work
without having to do the stuff in
http://docs.ansible.com/intro_installation.html#running-from-source so
it's a tad nicer for Python programmers who are accustomed to installing
packages as editable/in development mode.

Fixes GH-8355 (https://github.com/ansible/ansible/issues/8355)
Fix issue #8578. Setting envvar in ""'s ensures the PYTHONPATH is set to
include the lib/ directory.

Before - PYTHONPATH is empty.. ansible fails to run

    $ source hacking/env-setup.fish
    Appending PYTHONPATH

    Setting up Ansible to run out of checkout...

    PATH=/Volumes/opt/src/ansible/bin /usr/local/share/python3 /usr/local/bin
    /usr/bin /bin /usr/sbin /sbin /usr/local/bin /opt/X11/bin /usr/bin /sbin
    /usr/local/bin /Users/ms/bin/
    PYTHONPATH=
    ANSIBLE_LIBRARY=/Volumes/opt/src/ansible/library
    ...

    Traceback (most recent call last):
      File "/Volumes/opt/src/ansible/bin/ansible", line 25, in <module>
          from ansible.runner import Runner
          ImportError: No module named ansible.runner

After change - it's set.. ansible runs.

    source hacking/env-setup.fish
    Appending PYTHONPATH

    Setting up Ansible to run out of checkout...

    PATH=/Volumes/opt/src/ansible/bin /usr/local/share/python3 /usr/local/bin
    /usr/bin /bin /usr/sbin /sbin /usr/local/bin /opt/X11/bin /usr/bin /sbin
    /usr/local/bin /Users/ms/bin/
    PYTHONPATH=/Volumes/opt/src/ansible/lib:
    ANSIBLE_LIBRARY=/Volumes/opt/src/ansible/library
    ....

    $ ansible
    Usage: ansible <host-pattern> [options]
Merge pull request #8579 from hahla/devel

Fix issue #8578. Setting envvar in ""'s ensures the PYTHONPATH is set to
need to handle the case where include_pattern and exclude_pattern exist in the config file but contain empty strings
fixing "else" typo
Merge pull request #8580 from mpeters/ec2_inv_empty_patterns

Handle the case where include_pattern and exclude_pattern exist but are empty strings
Update keystone_user doc for tenant_description

The description var should be tenant_description.

Closes-bug: #8299
Fix some spelling mistakes in intro_windows.rst
Homebrew module: Added `+` and `.` characters to the package name regex.

Solves installation failures for packages like `bonnie++` or
`virtualhost.sh` as described in #8413.
Fix typo: & -> and

`and` is the boolean operator for AND in [Python][1].
`&` is the bitwise operator for AND in [Python][2].

[1]: https://docs.python.org/2/reference/expressions.html#boolean-operations
[2]: https://docs.python.org/2/reference/expressions.html#binary-bitwise-operations
Merge pull request #8587 from ericwb/bug/8299

Update keystone_user doc for tenant_description
Merge pull request #8589 from huckphin/huckphin-fixSpellingWindows

Fix some spelling mistakes in intro_windows.rst
Merge pull request #8612 from mjaschen-forks/devel

Homebrew module: Added `+` and `.` characters to the package name regex.
Merge pull request #8622 from ciupicri/typo

Fix typo: & -> and
Fix vault_password positional args error
Fixing variable name bug introduced in ac8950f

Fixes #8617
Fix host pattern matching and enhance error detection

Fixes #8614
Use match() instead of search() for pattern matching

Also related to f48fa3, fix for #8614
Load group_vars for new groups loaded via add_host

Fixes #8605
Catch error in atomic_move when creating temporary file

Fixes #8480