SQL tweaks.

The most notable change is that database credentials are no longer hardcoded into the source code, rather included from a settings file -- which is a standard and well understood practice.

Also, the provided SQL dump to set up the database has been cleaned up a bit:
* Useless PMA comments are gone ;
* The charset has been changed from latin1 to UTF8 (we are dealing with URLs here, and UFT8 is better for portability) ;
* The auto increment offset is gone - it made no sense for new installations.