Merge pull request #315 from ciranor/master

Remove unnecessary log messages
Fix #316, only cast to a list when a base string.
chef metrics are not counters, they are gauges

Changed default metric type as gauge instead of counter
Fixes #318, this forces the port to be an int
Merge pull request #317 from bergerx/master

Chef metrics are gauge not counters
Move to using publish_gague and fix the call check
Fix pulling the list of databases to return all values
Set datname in metric if it's part of the query (otherwise use the connected db name)
Restrict catalog / sequences from size metrics
Add additional fields to table stat io metrics
Fix stat name for database stats to be compatible with previous postgres collector
Add legacy database connection counts (supplemented by more specific connection state metrics)
Require config value `extended` to enable additional stats
Use correct registry for basic/extended metrics
Better decorator syntax for registration of metrics
Fix metric names for compatibility
PEP8 fixes
Add comment for set_isolation_level
Add comment explaining multi_db
Fix support for underscore config argument