Database operation libraries

This is a support library for my database abstraction libraries, but also serves as a 'main page' from which you can visit the libraries that make use of this one.

• sqlite4dm: Use an SQLite database backend for your world
• mysql4dm: Use a MySQL/MariaDB database backend for your world
• pgsql4dm: Use a PostgreSQL database backend for your world (recommended)
• dbchangelog: Record changes to your SQL databases and manage upgrades (recommended)