Recommended DB schema changes

Changes against schema.sql:

• Create towns table that is synchronized with towns from the map on each TFS start. town_id in players and houses will not have foreign keys or if they will, will not CASCADE DELETE.

• Add foreign key in table houses for owner to players. It makes sense to require that the owner is a valid player in database. Do not CASCADE DELETE.

• Add foreign key in table houses for highest_bidder to players. It makes sense to require that the highest bidder is a valid player in database. Do not CASCADE DELETE.

• Rename creationdata column to created_at in guilds table.

• Change collation from default/unspecified to utf8_unicode_ci/latin2. Not useful for Tibia Client but OTClient supports ISO/latin2.

• Put bug reports into database.