Add a bit redesigned "database" module.

Not yet complete.
 - Database class with some helper method
 - Database class with Result handling methods and properties
 - MySQL 'driver' and config

Plans:
 - PDO, SQLite 'driver' classes
 - SQLBuilder (probably imported from the https://github.com/c9s/php-SQLBuilder project)
 - support for prepared statements
 - etc...