Release 1.4.2

This is a minor bugfix release that fixes the following issues:

• Translate empty strings into NULL instead of 0.0 for columns of type double.
• Consistently quote table names to handle upper case table prefixes correctly.
• Avoid querying geometries in stage 2 of the flex output when expiry is disabled.
• Fix syntax error in index creation with schema enabled.

The release also adds a new osm2pgsql-replication script to simplify the process of downloading and applying updates. It requires pyosmium and psycopg2. See #1411 for more information.