Add PostGIS container rather than just bare bones postgres
Make container image a class constant

Syntax error
Merge remote-tracking branch 'origin/postgis-container'
Before returning service available, make sure port is connectable
Pylint fixes
Use port_open instead of raw socket
Pull out container start from ensure_container
Split out waiting for a port to become available
When starting Postgres, wait until it's available before return
Fix PostGIS CHECK_COMMAND
Pylint fixes
Slight error in timeout
Split wait for truthy into a helper method
Change TCP timeout to 30sec
Change allowed_exceptions to default val
Trailing comma on import