Issue #16424: List all providers when creating salt-cloud instance without profile

For this purpose `self.opts['providers']` is as good as `mapper.map_providers_parallel()`
Return empty dict for list_pkgs(purge_desired=True) with macports

This fixes #16828
Improve filter_by() base argument:

  * Change filter_by() base argument to a key in lookup_dict rather
    than a dictionary.  This allows more compact usage and more
    readable use of base values/defaults in the lookup_dict.

  * Change/improve function-local documentation for lookup_dict().

  * Add specific use-case of "base" argument for lookup_dict() in the
    formulas documentation.

  * Expand filter_by() unit testing to validate use of base argument.

  * Add unit test for salt.utils.dictupdate.update() to provide
    complete depth-of-testing of filter_by() which uses
    dictupdate.update().
Appease the pylint gods; back-out unrelated changes.
module that gathers vpc properties, returns dict
flatten and document get_returner_options().

Flattening the get_returner_options() func:
split into several funcs, return early when possible.

Document all arguments (it appears usage is quite a bit complex).

PEP8 almost everything.

(This code is ran very often in Salt. Hello Jenkins!)
Merge remote-tracking branch 'upstream/develop' into develop
Don't execute query if test mode is enabled.

Fixes 16756
Fixing salt.modules.zpool.exists
Chechking if zpool is present on the system
Adding functionality to create zpool with raid1 or raid2 or raid3. Fixes #16972
Added the ability to mount on OS X

- This uses the /etc/auto_master config to setup persistent mounts (always as the user running salt)
- As of right now only the root user can read the mount if it's mounted persistently (I recommend simply running this as another user and not persisting)
- Replaces the defaults setting to noowners on OS X
#16991 Fixed pylint issues
Fix to handle another error (function not implemented) generated when copying files on an SMB share from an OS X host.
Removes invalid BUFFSIZE argument from sc query / sc qc
Merge branch '2014.7' of https://github.com/saltstack/salt into develop
Adding ability to export zpool in salt.modules.zpool
Adding ability to import zpool in salt.modules.zpool
Adding ability in salt.modules.zpool.import to list available pools for import
Fixing pylint violation