Use the warnings module to display the git version message.

This allows us to ignore the error:

```python
    warnings.filterwarnings(
        'ignore',
        category=UserWarning,
        module='salt.version'
    )
```
Or, make it raise an exception:

```python
    warnings.filterwarnings(
        'error',
        category=UserWarning,
        module='salt.version'
    )
```
Remove the warnings filter from `salt.version`.
Added support for adding postgres user to group in state.
Added state for managing postgres groups
Don't unsubscribe, there is no need to and it leaves zeromq

in the wrong state for a few moments and breaks the client
Merge pull request #3299 from seanchannel/develop

update "hacking" files to match
Default "refresh" to False in pkg.upgrade (apt)

This fixes #3300. Also made pep8 fixes. python-mode FTW!
Fix #3300

Per @thatch45, pkg.upgrade will still default to refresh=True, but
list_upgrades will gain a "refresh" argument (which will also default to
true). This behavior will become the new default when #3210 is
implemented.
split reading conf file from actual configuration

This should allow for configuring salt without a conf file on disk,
useful when embedding salt in other systems and running tests.
forgot some occurences of load_config
Merge pull request #3302 from archtaku/issue3300

Add "refresh" to pkg.list_upgrades (apt)
Merge pull request #3285 from s0undt3ch/features/versions-warnings

Use the warnings module to display the git version message.
Merge pull request #3298 from shadowfax-chc/postgres-group-state

Postgres group state
Merge pull request #3305 from HonzaKral/develop

split reading conf file from actual configuration
Add skipif to a test that requires root