pep8 fixes
replace double quotes by single quotes
cleanup infinite calls _connection_defaults()
use db setting/variable as was said in documentation
fix pep8
fix version(): `psql --version` return client version, but we need server version
* fix db_list(): instead plain list with dbs properties return well formed dict
* fix docstring in _connection_defaults()
* fix _psql_cmd(): search psql by salt.utils.which
cleanup db_exists()
cleanup db_create(): we no need to check psql, which provide excellent diagnostic messages and return codes.
cleanup db_remove(): we no need to check psql, which provide excellent diagnostic messages and return codes.
fix user_list():
  * multiline query was cause shell error
  * parsing code wait for 13 cells in SELECT result, but query return 12 cells
  * query was not work with pgsql prior 9.1
replace internals user_exists() by call user_list()
pep8 fix
pep8 fix
pep8 fix
get server version by sql query
fix version() usage
* get rid of check_or_die() which is depricated
* use proper import
Merge pull request #3691 from archtaku/docs

Add version spec info to 0.13.0 release notes
Removed default value for cwd

This was preventing the logic for divining the default value based on
the current user in the execution module meaning that states specifying
a non-root ``user`` param also needed to specify a ``cwd`` param.
Updated more occurances of a default cwd